Category Archives: analysis

How Harimoto Built A 3-1 Lead And How Ma Long Came Back at the 2020 World Cup

In anticipation of the Tokyo Olympics, we are re-watching some key matches over the past year between top gold medal contenders. In this post we take a look at how Tomokazu Harimoto built a 3-1 lead against Ma Long at the 2020 World Cup before Ma called a pivotal time-out in Game 5 to come back and take the 4-3 win.

The 2020 World Cup was a weird tournament that likely makes its results a poor predictor of what will happen in the Olympics. First of all, it was right after the break from the pandemic, so players were still getting into competition state both mentally and physically. Second, players who integrated new elements into their game during the pandemic break were debuting them against the top competition often for the first time, possibly resulting in some more experimental play. Third, non-Chinese players had to go through onerous quarantine before entering China during which they were not allowed to train.

Nevertheless, there is still some signal to be gleaned from this tournament. We take a look at what happened in this match, what trends we can expect to persist at the Olympics, and what we can expect to be different. At the time of this posting, the full match can be viewed on Youtube.

Game Plan

We first take a look at the general way in which Harimoto and Ma scored points in this match. As is common practice by top Chinese-speaking players, we divide the point into two distinct phases: the first three shots and the ensuing rally.

First Three Shots

Fighting for the Half-Long

Ma Long’s most desirable outcome coming out of the first three shots of the point was for him to take a forehand opening against the long and especially the half-long ball. He won 68% of the points where he attempted (points in which he missed his opening are also counted) such an opening against a serve or push. On all other points, he was only able to win 47% of the points.

As shown in the clip below, one way that Harimoto, aware of the advantage that yielding the half-long gave to Ma Long, responded to some of Ma’s slower half-long openings was to go for a counter-kill and end the point immediately. Harimoto ended up landing four counter-kills and missing six counter-kills/blocks. This is still a losing situation but less so than when he let Ma control the point following the half-long and slowly carve him up.

The Flicking Game

After Ma was able to take six long forehand openings in game 1, Harimoto, unable to beat Ma in the short-pushing game, was more aggressive in attempting to flick against the short ball in the next game in order to deny Ma the half-long opening. In game 2, Harimoto took 9 short flicks as he cruised to an 11-3 victory. Harimoto would continue to be far more aggressive than Ma in attempting short flicks: Harimoto attempted 50 flicks in the match, while Ma only attempted 12.

Not only was Harimoto more aggressive in attempting to flick against the short ball, but his flicks themselves were also of a more aggressive nature. Harimoto landed 10 flicks that were instant winners while Ma only landed 4 such winners (and unlike Harimoto’s hard flicks, Ma’s “winners” were more controlled well-placed slow shots). However, Harimoto’s aggressiveness came at a cost: he also missed 7 short flicks while Ma did not miss a single flick.

Unforced Errors

We define an unforced error as a missed serve, serve return, or third ball opening against a push. The disparity in unforced errors was quite large as Harimoto missed five serve returns and four third balls while Ma only missed one serve return and one third ball against a push. That amounts to a seven-point difference for an average of one per game. Unforced errors didn’t end up being a difference-maker in any individual match, but the disparity is something to pay attention to should these two players meet in the Olympics.

Was the gap in unforced errors mostly due to extrinsic forces such as Harimoto’s onerous quarantine that Harimoto can easily take care of at Tokyo? Or was it mostly due to something intrinsic to their games such as Ma’s better serves and Harimoto’s natural inclination to take riskier openings?

Rally Game

Once the point got past the first three shots, Ma homed in on steadily attacking Harimoto’s elbow, often with a step-around forehand loop, as shown in the clip below.

Meanwhile, Harimoto played at a more frantic pace, going for fast wide kill-shots to Ma’s forehand, which was often extra vulnerable due to Ma’s tendency to step around. The most potent way in which Harimoto attacked Ma’s forehand was with a quick down-the-line backhand punch—either from the wing or from the elbow—with sidespin that curved the ball even wider to Ma’s forehand.

Alternatively, against Ma’s many shots to the elbow, Harimoto could also step around to deliver a quick forehand loop that was placed even wider and curved even harder than his backhand punch. These step-around shots from the elbow carried the advantage that Harimoto could generate his own power with a quick backstroke and not have to rely on borrowing Ma’s pace. However, the downside was that the extra backstroke made the shot harder to pull off in a faster rally, in which case the quick backhand would be preferred.

Ma typically waited until he had the opportunity to step around for a big forehand before going to Harimoto’s forehand. However, Ma would leave his forehand extremely exposed in such instances, which Harimoto took advantage of with wide quick blocks off the bounce.

Ma Long’s Magical Time-Out

Harimoto looked on his way to a 4-1 victory as he had just scored three straight points and was up 5-4 and 3-1 in games until Ma called a time-out and completely reversed the course of the match.

Ma’s Magical High-Toss Serve

Prior to the time-out, Ma served a high-toss serve only twice. After the time-out, every single one of Ma’s serves was a high-toss serve. Ma’s high-toss serve was absolutely devastating for Harimoto. After the time-out, Harimoto held his own on his own serves through the second half of game 5 and game 6, going 7-7. However, he went an abysmal 2-11 on Ma’s serves.

Harimoto appeared to struggle mightily with pushing short against the high-toss serve, presumably due to an inability to read how much spin was on the ball. As a result, one major effect of Ma’s high-toss serve was that it opened up far more opportunities for him on the half-long opening. In Games 2-4 and the first half of game five, in which Harimoto was largely in control, Ma attempted a long forehand opening on 14% of the points. After the time-out, Ma nearly doubled that number to 26% over the next game and a half.

One way Harimoto managed to deny Ma the half-long was to flick the serve. However, against the high toss-serve, due to difficulties reading the spin and the inherent challenges of giving quality flicks against no-spin or light-spin balls, Harimoto’s flicks likely packed just a bit less speed and spin than earlier in the match. The slow-down appeared to be enough for Ma to wait in anticipation for the hard counter from the backhand or elbow and continue to dominate these points.

Taming Harimoto’s Fast Wide Shots to the Forehand

One of Ma’s key adjustments after the time-out was taking away the fast wide shots to the forehand from Harimoto. Both Harimoto’s number of attempted fast wide shots to the forehand and their effectiveness vanished following Ma’s time-out in Game 5. Before the time-out, Harimoto was able to land a fast wide shot to the forehand on 36% of all points and convert 89% of those into a win. However, after the time-out, Harimoto was only able to land a fast wide shot on 21% of all points and convert a measly 44% into wins.

The lower number of attempts is likely a consequence of Ma better controlling the rhythm of the point thanks to his high-toss serve. The lower conversion rate was likely due to Ma better anticipating the fast wide shot to the forehand so that he could get in position more reliably like in the clip shown below. In the first point of the clip, even though Harimoto misses the shot, we can see that Ma was already waiting for the shot to the forehand.

What to Expect In Tokyo

Should Ma and Harimoto meet in Tokyo, the aesthetic of the match will likely be similar, with Ma hunting half-longs and attacks to the elbow and Harimoto more aggressively flicking short balls and trying to win the rallies with quick wide shots to the forehand.

Harimoto will clearly be looking to make certain adjustments. Most importantly, he needs to find a way to better read Ma’s high-toss serve and develop a better contingency plan in case he has trouble reading the high-toss serve (or a new serve) again. Harimoto will also likely look to clean up some of the errors he made at the World Cup by virtue of better shot selection and being in better game-shape come Tokyo.

At age 33, Ma has likely been coasting through most of the major events since the 2019 World Championships, and we can expect to see an all-around better version of Ma in Tokyo. While Ma cannot count on his high-toss serve to bail him out again at the Olympics, he also still has more tools in his bag of tricks (such as his backhand serve) to give him an extra advantage should he need it again against Harimoto.

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Identifying The Magnus Effect In Table Tennis

As we all wait for the elite professional table tennis scene to return in early May, in today’s post we will look at one of the more fundamental physical phenomena in table tennis that not all viewers are aware of: the Magnus Effect.

The Magnus Effect is a physical phenomenon that explains how the spin of a ball modifies its trajectory while the ball is in the air. Unlike other aspects of table tennis mechanics, the Magnus Effect is not the result of gravity and friction, forces that we are familiar with and experience every day, but the result of fluid dynamics. This makes it difficult to visualize and form an intuitive understanding of the Magnus Effect.

However, although it is difficult to create an intuition for the cause of the Magnus Effect, once you understand its results (which are extremely simple), then you can see how the Magnus Effect is present in several common table tennis contexts.

What is the Magnus Effect?

A very non-rigorous explanation of the Magnus Effect (courtesy of Wikipedia) is as follows. When a spinning ball moves through a fluid (such as air), the ball “pushes” the air in one direction, and as a result of Newton’s Third Law (every action has an equal and opposite reaction), the air pushes back on the ball in the opposite direction. The visualization below shows a ball with topspin traveling to the right, which kicks up the air behinds it. As a result, the air exerts a reactive downward force on the ball.

If this is difficult to form an intuition around, that is fine; from a table tennis perspective what matters is not the cause but the effect of the Magnus Effect. The most important takeaway is that the Magnus Effect means that the spin of the ball affects its trajectory while the ball is still in the air and before it even hits the table.

Visualization of the airflow that causes the Magnus Effect

What makes the Magnus Effect counterintuitive is that for topspin and underspin, the direction of the force is opposite of what we usually associate for each spin. When the ball bounces on the table or off the raquet, we typically associate a topspin ball with jumping upward and forward (e.g. for a kicker serve) and an underspin ball will jump downward and backward (e.g. Ma Lin’s famous ghost serve).

However, by contrast, the Magnus Effect exerts a downward force (and a smaller backward force when the ball is falling) on topspin balls and an upward force (and a smaller forward force when the ball is falling) on underspin balls. We can better visualize both the direction of the Magnus Effect and how strongly it can influence the ball’s trajectory in the below video, where a basketball falling downward with backspin floats very far forward. If you tilt your neck sideways while watching the video, then you can see how a ball with backspin traveling horizontally across a table will feel an upward force due to the Magnus Effect (of course, in a table tennis scenario, this force is still weaker than gravity, so the ball still falls down onto the table).

Identifying the Magnus Effect in Table Tennis

At its essence, the Magnus Effect may be slightly counterintuitive but it is extremely simple: topspin is dragged down when the ball is in the air, and underspin is lifted up when the ball is in the air. We look at its consequences in two common scenarios: the fast topspin rally and the counter against a spinny opening loop.

The Magnus Effect In Fast Topspin Rallies

One of the biggest results of the Magnus Effect is that it is more desirable to add topspin to loops regardless of the speed. Spin vs speed is often viewed as a tradeoff where one must lose one to gain the other, which can be the case when the amount of spin/speed generated is limited by the player’s physical abilities. However, in the certain in-game contexts, increasing topspin may actually enable more speed. Watch the following winner by Ding Ning below.

The radar on the net measures the speed of the winner to be a fast 70 km/hr, but notice how the ball actually does not bounce that deep on the table. It only bounces roughly at the halfway point between the edge and the net both on Ding’s game-winner and the shot immediately before that. This is because the ball is loaded with spin (watch the ball roll on the floor when the point ends), so a heavy Magnus force drags the ball down faster. Hence, Ding Ning could have hit even faster, and the ball would still have landed within the table.

In general, adding more topspin counterintuitively makes the ball land shallower due to the Magnus Effect. This gives players a wider margin of error to hit the ball hard and fast without having to worry about it going off the table. As long as the player brushes the ball sufficiently and adds enough spin, the player can hit as hard as he or she wants and the ball will still drop down onto the table because of the increased Magnus force.

Although it is usually desirable to land serves, pushes, and opening deep onto the table, in the fast rally the ball is so fast and the opponent has so little time to react that the shallow depth appears not to matter much anyway. Moreover, with the heavy amount of spin involved and high downward velocity due to the Magnus Effect, the ball gets a serious kick once it bounces off the table. Looking at the slow-motion replay you can see how much pressure Ding Ning applies to Mima Ito during that point. On the first block, the ball is already up to near her face-level (granted, Mima Ito is short and also bending down). On the second shot, Ito is a bit late, and the ball jumps over her paddle.

Leveraging the Magnus Effect Against Slow Spinny Loops

Many amateur players have had the experience where, even if an opening loop is slow, if it is spinny it can often be quite challenging to block because the spin causes the ball to bounce off the racquet so that it flies off the edge of the table. One solution is to close the racquet and essentially hit the ball downward in order to counter the heavy topspin..

Alternatively, a player can simply add his or her own topspin to the ball, so even if the ball bounces off the racquet at a higher angle than expected, the Magnus Effect will forgive minor errors and drag the ball down. In the clip below, Ma Long opens his angle and counters Fan Zhendong’s slow spinny opening with a heavy topspin counter in which his racquet goes almost straight up instead of down or even forward.

Bonus: Around-the-net Shots

The Magnus Effect carries the most in-game implication for top-spin balls and topspin is usually the heaviest spin in the match, but it also affects heavy underspin and sidespin balls. For underspin balls, the Magnus Effect gives heavy chops their floating effect. While the distances involved in table tennis are too small for us to see some of the extreme bends that we do in soccer/football on sidespin balls, the curve induced by the Magnus Effect can clearly be seen in some of the more ambitious around-the-net shots that Youtube stars like Adam Bobrow take.

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Unfortunately, ITTF has killed ITTV, meaning that past matches are no longer publicly available to watch. Hence, no analysis blog posts are scheduled for the immediate future. You can check out past analysis posts here.

Analyzing Jeon Jihee’s Evolving Service Strategy Against Mima Ito

As a medal contender at the Tokyo Olympics, Jeon Jihee has a chance to make Korean Olympic table tennis history this summer. The most recent Olympic singles medals for South Korea are Kim Kyung-ah’s bronze medal in the 2004 women’s singles event and Ryu Seungmin’s famous gold medal in the 2004 men’s singles event. No woman from South Korea has ever reached the finals in the singles event. Similarly, the last time South Korea won a medal in the women’s team event was in 2008, and South Korea has never reached the finals in the team event.

Jeon Jihee has a puncher’s chance at accomplishing all of these things, but there is one player who consistently stands in her way to Olympic glory: Mima Ito.

Jeon’s Path To Olympic Glory

The Path to a Singles Medal

In the women’s singles event, there are roughly three tiers of medal contenders. In the first tier are the two yet-to-be-named Chinese women, who will be heavy favorites regardless of their seedings (although both will likely be top three seeds). In the second tier is second seed Mima Ito, who is quite widely acknowledged as the single most dominant threat to Chinese supremacy in the women’s events. In the third tier are seeds four through eight, which in order of projected Olympic seeding are Cheng I-Ching, Feng Tianwei, Kasumi Ishikawa, Jeon Jihee, and Doo Hoi Kem.

Let us first make the somewhat reasonable assumption that nobody in the third tier is able to pull off what would be a historically unprecedented upset against either of the Chinese women (although a historic upset is always possible and Jeon has beaten Chen Meng before in T2). Jeon’s viable path to an Olympic singles medal without having to defeat a Chinese player is as follows.

As a top-eight seed, Jeon is guaranteed not to play anybody higher ranked than her until at least the quarter-finals. In order for her to have the best chance to medal, she has to hope that she can avoid the Chinese players in the quarter-finals by drawing either Ito or the fourth seed. If Jeon is able to upset both the fourth seed and Mima Ito in some order, then she wins at least a bronze medal.

While it is unclear how the Olympic seeding rules work out this year, there is a chance that the two Chinese players may end up on the same half of the draw, in which case if Jeon defeats the fourth seed and Ito, then she will reach the Olympic finals.

The Path to Team Glory

With Jeon’s presence and the rise of teenager Shin Yubin, who notched impressive wins over Miu Hirano and Miyuu Kihara at WTT Doha and steamrolled the domestic competition at the Korean Olympic trials, Team Korea looks to be at the very least a bronze-medal contender and arguably the bronze-medal favorite in Tokyo. However, Korea appears to have loftier expectations.

In a press conference on March 15 (English translation on TTD), Korean table tennis legends Ryu Seungmin and Kim Taeksoo said that they believe that Korea has a solid chance at upsetting Japan and taking the silver medal (Kim also believes that only Japan can reasonably challenge China) at the Olympics. This is a bold proclamation as Japan’s lowest ranked player, Hirano, is higher ranked than Korea’s highest ranked player, Jeon. However, Korea has pointed to recent encouraging signs in their favor, particularly Shin’s win over Hirano and Shin/Jeon’s doubles win over Hirano/Ishikawa at WTT Doha.

Korea is likely closely monitoring the progress of Choi Hyojoo and Shin Yubin before making any final lineup decisions. However, from their remarks, Ryu and Kim seem to be signaling that Jeon and Shin will be playing the doubles match and that Shin will be playing singles against Hirano or Ishikawa. 

If that is the case, then Choi will play a singles match against Ito, who Choi came close to beating at the 2019 World Team Cup, and Japan’s choice of Hirano or Ishikawa, and Jeon will play Ito in a critical singles match should the two countries meet in the semi-finals.

Given that Jeon’s finals aspirations in both the team event and singles event likely run through Mima Ito, should Jeon spend the next few months hyper-focused on Ito similar to the way that China appears to be?

What are Jeon Jihee’s chances of pulling off the wins that she needs?

Jeon appears to have reasonable chances of upsetting the fourth seed in the women’s singles event (who will likely be Cheng I-Ching, Feng Tianwei, or Kasumi Ishikawa). Since 2018, Jeon is 4-3 against Cheng, 2-3 against Feng, and has not played Ishikawa in international competition. As we saw in WTT Doha, there is also a sizable chance that the fourth seed is not even able to make it to the quarter-finals.

On the other hand, we also saw in WTT Doha that Mima Ito appears to arguably be heads and shoulders above the rest of the non-Chinese competition, including Jeon. Since 2018, Jeon is 0-4 against Ito, including two 4-1 losses since the pandemic. Jeon will almost certainly walk into Tokyo as an underdog against Ito.

Although Jeon has had an underwhelming history against Ito over the last couple of years, their last two matches have been closer than the 4-1 scores may indicate. Out of the eight games that Jeon has lost to Ito in the last several months, three have been heart-breaking deuces.

First, at the 2020 World Cup last November, Jeon was up 10-7 and then failed to convert on four game points in a row to lose 13-11. Then at WTT Doha in March, Jeon lost a deuce 17-15 after Ito got a critical net ball at 15-15 in the second game. In the fifth game, Jeon was again up 10-7 lead and lost six game points in a row, resulting in a 15-13 loss.

Given the closeness of some of these games, even marginal targeted adjustments against Ito may be enough for Jeon to tilt the game more in her favor and pull off the upset in Tokyo.

The Story of Jeon Jihee’s Service Strategy Against Mima Ito

Mima Ito’s Domination on the Serve Return

One adjustment to her game that Jeon has already made and may continue to make against Ito is in the service. Shown below are the last four game points that Jeon failed to convert in game five against Ito at WTT Doha as well as the only match point that Ito needed to win the match.

Over the course of five consecutive critical service returns, Ito manages to receive every serve with the short pips on her backhand and does whatever she wants to them to create an advantage for herself on the next shot. She lands three chiquitas of varying side spin, a fast straight backhand flick, and a strawberry flick.

Why is Ito able to so freely create whatever she wants when receiving the short ball? Part of the reason may be that she does not fully respect the threat of Jeon’s long fast serve to the backhand, which allows Ito to fully focus on being creative with the short receive. Can we quantify how concerned Ito is about the long serve to the backhand and by extension how little attention she can devote to the receive on the short forehand corner?

One rough proxy is the number of times she receives a long fast serve with her forehand. When Ito receives too many long fast serves to the backhand and feels like she is unable to create an advantage on them, she tends to step around and open using her forehand. If Ito has to plan to open her stance for a forehand loop and additionally move left if she’s stepping around, then in principle it should become more difficult for her to move into the table to the short forehand corner to receive a serve with the pips on her backhand.

In Ito’s 4-3 win against Hina Hayata at the All Japan National Championships in January, Ito attempted to receive 13 long serves with her forehand (note this number also includes Hayata’s long serves to Ito’s forehand). In her 4-2 win against Hayata at WTT Doha, that number was 16. In her 4-3 loss to Kasumi Ishikawa at the All Japan National Championships, that number was 5. What about in her 4-1 win over Jeon Jihee at the World Cup last November? Zero.

Jeon raised that number to three in Doha. Let us take a look at the adjustment she made to cause this change, and whether she should further adapt her service game specifically for Mima Ito like other top lefties appear to do.

How Other Left-Handed Stars Serve Against Mima Ito

Jeon may have already started to adapt her service pattern to be more in line with several other left-handed players who are strongly motivated to optimize their games against Ito: Hina Hayata, Kasumi Ishikawa, and Ding Ning. Hayata and Ishikawa should be deeply familiar with Ito since they compete with her for domestic as well as international titles. Ding Ning, along with the rest of China, is likely also hyper-focused on Ito as she is the single biggest threat to Chinese supremacy.

We show selected points in some of their matches against Ito in the past year. Note that these are all very important points in the match. For Hayata and Ishikawa, these are their last few serves in a seven-game thriller. For Ding, these are her last three serves in a 14-12 win during a pivotal third game.

Several things stand out. First, all three of them are willing to challenge Ito on the long serve, even if it means letting Ito step around for a forehand opening. Second, Ito doesn’t do anything too fancy against them when they do serve short. Third, when serving they all stand inside close to the middle of the table (as opposed to the more common position of standing behind the corner), which appears to give them the flexibility to execute serves short to the wide forehand or long to the wide backhand.

Hayata and Ding can go full games serving entirely behind the corner, even at 9-9, but they do serve from inside the table throughout the match, and it says something that when they need points the most, they opt to serve from inside the table. Moreover, while Hayata likes to serve from inside the table against everyone, Ding and Ishikawa are quite clearly serving more often from inside the table specifically because they are playing Ito.

To get a rough idea of how heavily Ishikawa changed her service game for Ito in the All Japan National Championships, consider the following numbers. In Ishikawa’s 4-3 win over Ito in the finals, Ishikawa served from inside the table 85 percent of the time. However, in her 4-2 win over Miyuu Kihara in the semi-finals, Ishikawa served from inside the table only 21 percent of the time.

In Jeon’s loss to Ito at the World Cup, Jeon didn’t serve from the inside the table even once. This is in line with her and Ding Ning’s typical service pattern: almost always serve from behind the corner and possibly break out a different serve from inside the table to introduce some surprises during critical points.

However, at least Ding and Ishikawa have both apparently decided that such a service pattern is sub-optimal against Mima Ito. Jeon seems to have arrived at a similar conclusion as she heavily integrated more serves from inside the table at WTT Doha.

How Jeon Jihee Changed Her Serves At WTT Doha

Jeon Jihee notably started serving from inside the table against Mima Ito at WTT Doha in the second halves of Games 2, 3, and 5 after never doing so in the World Cup (she did, however, serve at least once from the center of the table in her 3-1 loss to Ito at T2 in 2019).

We caught glimpses of the potential advantages of using this serve. In the clip below, we see Jeon take a pair of points at 9-9 in the third game off two fast long serves to the backhand. Ito can only give a standard backhand flick return that is not particularly fast due to the short pips, which Jeon can take advantage of.

However, this serve is not a silver bullet to cure all of Jeon’s woes against Ito. Due to a combination of Ito’s brilliance and Jeon’s possible lack of familiarity with her own serve, some of Ito’s returns against this serve seemed to really catch Jeon by surprise. Jeon also may have signaled more information than she would like with her service stance; she was far more likely to serve fast and long to the backhand when standing inside the table. She can remedy this by serving to the short forehand from inside the table more often.

Jeon also almost certainly feels more comfortable with her usual serve from behind the corner. While she can surely execute her serve from inside the table perfectly during training, can she do it repeatedly when the pressure is on?

As seen in the first video clip in this post, to close out the match Jeon reverted to her normal serve from behind the corner even though Ito was having her way with them. Was this a tactical decision or was it because Jeon lost confidence in her ability to execute the serve well? Jeon did serve a long fast serve to the backhand from inside the table at 12-11, but Ito seemed to easily take advantage of it since the serve was predictable and/or not executed well.

It remains to be seen whether Jeon further integrates this serve into her matches against Ito in the future. At Doha, she only used this serve in the second half of a game and only if the score was within two or three points. This is roughly on par with (although possibly slightly less than) how often Hayata and Ding use this serve against Ito. Does Jeon want to fully adapt Ishikawa’s strategy in All Japan and essentially make this her default serve?

How Much Does Jeon Jihee Want Mima Ito To Step Around?

Counting the number of times Mima Ito receives a long serve with the forehand is always an interesting exercise. As mentioned earlier, the upside of Ito stepping around is that it means she can devote less attention to the short forehand corner. The downside is that it allows her to open with an aggressive shot.

However, a step around forehand from Ito may not be as scary as it sounds. Sure, if Ito knows exactly where the ball is going and has time to prepare, she can pretty much score an immediate winner with a fast wide smash to either corner. However, when she is on the move, not completely in position, and hitting it from a wide angle on her backhand corner, it is extremely difficult to go hard straight down the line to the left-handed server’s backhand.

The points shown below are quite illustrative of the risks and rewards of Mima Ito stepping around for the forehand opening on the serve return.

In the first point, Ito is only able to make a soft and somewhat predictable cross-court shot to Jeon’s forehand, and Jeon lands the strong counter-loop. In the second point, Ishikawa is waiting for the forehand counter, but Ito manages to get in position and land a smash to her elbow for the instant kill. In the third point, Ito prepares to step around, but Ishikawa serves short to the forehand, so Ito can only push with the forehand. Ishikawa loses the point, but she gets a desirable serve return from Ito.

No set formula exists for how often the opponent should want Ito to step around and take the forehand serve return opening. Even Ito probably does not know the optimal number. Hayata, Ding, Ishikawa, and Jeon (listed in order of willingness to challenge Ito’s long opening attack) have all tried various service strategies with varying degrees of success.

So far Ding has had the most success against Ito, but that can also be heavily attributed to the fact that she is Ding Ning. Meanwhile, Jeon has so far been the most conservative with the worst results (granted there are many other factors that account for her results), and it remains to be seen whether she will further adapt her strategy going forward.

If you liked this post, please share it with your friends and follow Edges and Nets on Facebook , Instagram, and Twitter to stay updated.

Unfortunately, ITTF has killed ITTV, meaning that past matches are no longer publicly available to watch. Hence, no blog posts are scheduled for the immediate future. You can check out past analysis posts here.

How Dimitrij Ovtcharov Solved The Lin Yun-Ju Problem At WTT Doha

A guide to all of Edges and Nets’ coverage of WTT Doha (also known as World Table Tennis (WTT) Middle East Hub and formerly known as ITTF Qatar Open) can be found here.

Dimitrij Ovtcharov appeared to have a Lin Yun-Ju problem. Going into WTT Doha, Lin had won their previous four match-ups in international competition dating back to the 2018 Austrian Open and appeared to have virtually no problem attacking Ovtcharov’s famous serves or dominating Ovtcharov in the rallies.

However, with several key adjustments Ovtcharov actually came quite close to beating Lin in the ITTF Grand Finals in November 2020, but he fell just short, losing deuce in the sixth game. After adding in a few extra wrinkles to his game, Ovtcharov was finally able to snap his losing streak against Lin in the WTT Contender finals at WTT Doha witha 4-1 victory. We take a look at what adjustments Ovtcharov made to finally solve the Lin Yun-Ju problem on his fifth try.

Unfortunately, the video of the full match appears to have been removed from Youtube and to the best of our knowledge is currently publicly unavailable.

The Lin Yun-Ju Problem

We note two key reasons for Lin’s dominance over Ovtcharov in their previous matches. First is that although Ovtcharov’s serves are typically seen as one of his strengths, Lin has virtually no problem receiving Ovtcharov’s serves with very aggressive chiquitas that allow Lin to take the initiative on the attack. Second, Lin appears to be physically faster than Ovtcharov by a comfortable margin, allowing him to dominate in fast-paced counter-attack rallies as shown in the point below from their match in 2020.

Thus, Ovtcharov will almost certainly lose to Lin if he plays the traditional approach that most young kids are taught of trying to land the first opening attack and using the advantage gained from taking the initiative to dominate the ensuing rally. Ovtcharov cannot compete with Lin’s chiquita to open up more often than Lin. Even if Ovtcharov were able to open up first more often than Lin, Lin’s physical speed advantage could effectively neutralize the advantage Ovtcharov may gain in the rally from being the first to open.

The Solution: Ceding the Opening Attack

After losing quite handily in the 2019 Czech Open, one of Ovtcharov’s central and incredibly daring and innovative adjustments both in the 2020 ITTF Grand Finals and in WTT Doha was to almost completely cede the opening attack to Lin.

To get an idea of how willing Ovtcharov was to allow Lin to attack first, consider the following numbers. In their 2019 match-up, Ovtcharov attempted 36% of the opening attacks (whether make or miss) from either player. While Lin attempted a healthy majority of the opening attacks, this is still quite a reasonable number given his dominance in the chiquita.

In the 2020 Grand Finals, Ovtcharov attempted only 20% of the opening attacks, allowing Lin to open up a staggering four times more often than Ovtcharov did. Ovtcharov returned over half of Lin’s long or half-long serves with a push or defensive shot, a decision that would earn most young children a healthy punishment from their coach. For comparison, in their 2019 match-up, in which Ovtcharov played a more conventional approach, Ovtcharov attacked nine of Lin’s eleven long serves.

Ovtcharov continued this approach of pushing long serves in their match at WTT Doha, even doing so at game point and deuce as shown below.

Overall, in Ovtcharov’s victory at WTT Doha, he attempted a more reasonable 30% of the opening attacks. The uptick in attempted opening attacks can be explained by several factors. First is the statistical noise present in any sample size of roughly 100. Second, as we will see later, Ovtcharov appeared to intentionally mix in more attacks to catch Lin off guard more often.

Third is that Lin also made the observation that Ovtcharov was perfectly happy to let him attack first and adjusted his game accordingly. This could most clearly be seen in that he pushed several of Ovtcharov’s serves as opposed to rushing in for the chiquita. Lin virtually never made such a move in their matches in the 2019 Czech Open and the 2020 Grand Finals. This adjustment in turn allowed Ovtcharov to reveal just how happy he was to let Lin attack first; Ovtcharov simply pushed back Lin’s pushes and did not seem to mind if his own push ended up being long or even slightly high.

Why Cede the Opening Attack?

What does Ovtcharov gain from ceding the opening attack? After all, it often ends up with Lin immediately winning the point with a clean third-ball kill.

First is the obvious advantage that pushing is less error prone than attacking. In their two match-ups at the 2020 Grand Finals and WTT Doha 2021, Lin totaled 22 opening errors, while Ovtcharov only had 7. Over the course of 11 games, this comes out to just over one extra error a game for Lin. However, as Ovtcharov won two games in deuce in his 4-1 victory in Doha, this small advantage ends up mattering greatly.

However, Ovtcharov cannot just hope for Lin to miss 11 openings a game. The central advantage of ceding the attack appears to be that it counter-intuitively allows Ovtcharov to better dictate the pace and rhythm of the game. We can see this in a couple of Ovtcharov’s favorite go-to plays against Lin.

Go-To Play #1: Backhand or Elbow Pin-down Against the Chiquita

As shown in the two points in the video below, one of Ovtcharov’s favorite plays is to either serve or push short or half-long to Lin’s forehand and allow Lin to take a chiquita from the forehand. Ovtcharov then blocks down the line to Lin’s backhand or elbow, and Lin either misses the backhand or returns an extremely weak shot that gives Ovtcharov a massive advantage in the ensuing rally.

From this play, we see one big advantage of letting Lin attack first. Provided that Ovtcharov can to a certain degree anticipate the location of Lin’s first attack and avoid immediately getting killed, he is often firmly waiting in the position he wants to be at while Lin has to move his body further out both in the left-right direction and the shallow-deep direction in order to initiate the attack.

Thus, even if Lin knows that the ball is likely to go deep to his backhand on the next shot (which is not a guarantee if Ovtcharov plays with enough variation and keeps Lin guessing), he has a significant distance to cover and not much time (recall Ovtcharov is typically blocking down the line) to recover from his opening chiquita, neutralizing his physical speed advantage over Ovtcharov.

While Ovtcharov most clearly leveraged this positional advantage in the backhand pin-down against Lin’s chiquita from the forehand corner, it can also be seen in other points in the match, such as in the point below where Lin steps around for the hard forehand kill, but Ovtcharov correctly anticipates the location of the kill and blocks it wide to Lin’s forehand.

Go-To Play #2: Change In Pace

While Ovtcharov may have difficulty keeping up with Lin in terms of raw speed, he is able to throw Lin off rhythm by either going from a slow block to a fast counter or sometimes even a fast counter to a slower block as seen in the point below.

If Ovtcharov’s goal is to maximize change of pace, Ovtcharov may thus prefer to start from a position of blocking instead of a moderately fast opening attack as it allows him to switch gears more drastically. We can also see more clearly how Ovtcharov’s defensive approach actually makes his attacks more effective in several points where Ovtcharov performs a standard opening but appears to catch Lin off guard and win the point immediately.

Ovtcharov faces the standard trade-off where if he attacks too much, then his attacks are no longer surprising and he is unnecessarily playing into Lin’s game. This appears to have been the case in the 2019 Czech Open. However, attack too little and he is failing to exploit a quick and easy source of points. This appears to have been the case in the 2020 ITTF Grand Finals. Ovtcharov seems to have struck a nice balance of initiating the attack just under 30% of the time and pushing a little less than half of Lin’s long serves at WTT Doha. Of course, Lin may force a change in that number in their next match-up.

Extending The Bag of Tricks

One critical difference between Ovtcharov’s loss in the 2020 Grand Finals and his victory in WTT Doha is that in the 2020 Grand Finals, Ovtcharov lost a game 11-9 and a game in deuce, while in Doha, Ovtcharov won both the deuce games.

The change in results can arguably be attributed to luck or Lin playing slightly worse or Ovtcharov playing slightly better. However, Ovtcharov also helped himself in Doha by introducing new subtle tricks that allowed him to eke out the extra two games that he needed.

Perhaps the most clear addition to Ovtcharov’s bag of tricks was a new simple dead serve (Kong Linghui is another notable player to have used this serve) that was completely non-existent in his 2019 match with Lin. Ovtcharov was also hesitant to use this serve in their 2020 match until down 9-5 in the sixth game. The serve was effective enough for him to force the game to deuce.

In Doha, Ovtcharov was happy to use this serve much more frequently, even at deuce. It played well into his defensive approach to the game, and Lin was unable to do much against it as there was no spin or power to borrow. As mentioned earlier in this post, Lin chose to push the serve back in both the points shown below, but Ovtcharov felt comfortable pushing the ball back again to give the opening to Lin. The extra couple points won from this serve throughout the match helped give Ovtcharov the slight edge that he needed to take the two close games in the match.

What’s next?

Lin is now the front-runner over Hugo Calderano to take the fourth seed at the Tokyo Olympics. If Lin holds on to the fourth seed, a Lin-Ovtcharov quarter-final draw has a 25% chance of happening, Of course, both players need to also avoid getting upset in order for the match to actually happen. There is also a decent chance that these two could meet in a bronze medal match if Ovtcharov can replicate his WTT Contender performance against Harimoto and China continues to dominate. It is hard to say who would be favored in a match-up in the Tokyo Olympics.

On the one hand, Lin is higher ranked, has a history of defeating Ovtcharov, and appears to have a raw physical advantage in the fast rallies. Moreover, if Ovtcharov is really so eager to let Lin attack first, nothing is stopping Lin from just pushing the ball back more often. At the end of the day, as the one who initiates the attack, Lin in principle should have more control over the pace and rhythm of the game. Moreover, Ovtcharov’s tricks will lose effectiveness as their novelty wears off, and Lin is almost certainly training against the simple dead serve.

On the other hand, Ovtcharov almost certainly has more tricks saved up just for the Olympics, and he is likely to innovate more tricks and tactics over the next few months. Moreover, playing in the round of 16 in the ITTF Grand Finals or the finals of WTT Contender is a completely different animal from playing in a bronze-medal match at the Olympics.

Liu Shiwen has mentioned how critical the mental aspect of table tennis is and how her previous World Championship finals experience gave her the edge over Chen Meng in 2019. Lin is only 19 and has never played in any match as nearly as high stakes as an Olympic bronze-medal match. He may be the “silent assassin” when playing in a T2 or world tour event that, despite the prize money, in the grand scheme of things is quite meaningless, but we have yet to see him in such a big spotlight. On the other hand, this will be Ovtcharov’s third Olympics and he has already won a bronze medal in 2012, which may give him just enough of a mental edge to eke out a tight win.

We apologize for the delay in releasing this post as it took longer than anticipated to write. The next post is scheduled for Wednesday, April 7.

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6 Ruwen Filus Shots To Watch Out For In The WTT Doha Finals

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World Rank 42 Ruwen Filus has made a surprise Cinderella run to the finals of WTT Star Contender after defeating Jang Woojin (WR 12) in the round of 32, Jun Mizutani (WR 18) in the round of 16, Lin Yun-Ju (WR 6) in the quarter-finals, and Darko Jorgic (WR 31) in the semi-finals.

He will face Tomokazu Harimoto (WR 5) in the finals, and a sizable number of fans are expecting/hoping for Filus to win. The finals can be viewed on WTT’s website and will be streamed live at 12:45 Greenwich time. Harimoto and Filus have gone 1-1 in their previous international match-ups, with Filus winning their most recent match in 2019.

Although Filus, at age 33, has been around for a while, some fans may be quite unfamiliar with Filus’ game other than the fact that he is a chopper. Most people’s minds immediately jump to Joo Se Hyuk when they think of a male chopper, but Filus is quite different and arguably more creative. We re-watched Filus’ round of 32 match against Jang Woojin and identified six shots to watch out for in a Ruwen Filus match.

Each of these six shots have at least two or three variations visible to the spectator, and when Filus is able to string them together in weird combinations, the possibilities are countless.

Another thing to note is that most of these shots are actually offensive shots. While Filus is known as a chopper, if we discount lucky points and missed serve returns from from the opponent, in Filus’ round of 32 victory over Jang Woojin, 72% of the points that Filus won were on offensive shots (i.e. shots where Filus is actively and quickly trying to throw his opponent out of position). With that in mind, let’s now take a non-exhaustive look at Filus’ toolkit.

1) Offensive Shot: The Floater

The floater is an aggressive shot popular among close-to-the-table long pips players (which Filus is not). To execute the floater, Filus quickly pushes an underspin ball with the long pips at a well-placed location to the elbow or wide corner. While the ball’s raw speed is lower than a regular chiquita, the ball still comes back fast and opponents will sometimes get a unique sensation that the ball is “floating” towards them, which can often mess up their timing. Moreover, Filus appears to have more control over the direction and magnitude of the sidespin he adds to the ball compared to a standard chiquita.

While some may dispute the classification of this shot as an offensive shot due to its slow speed, Filus often uses it with the intent to either win the point outright or set up an aggressive opening on the next shot.

2) Offensive Shot: The Surprise Block

It may seem paradoxical to classify a block as an offensive shot, but the keyword is surprise. When the opponent is expecting Filus to chop it back slowly and then he rushes in and twiddles the paddle for the fast backhand block, the opponent has to react arguably just as quickly as if it were a counterloop or punch that they were expecting.

Unlike the floater, which Filus frequently uses to either win the point or set up another shot, Filus doesn’t use this shot as often (hence the term “surprise” in the name). However, when he does it, the conversion rate is very high.

The surprise block is typically a backhand shot, but there is a forehand variation where it looks like Filus is about to push or shovel (see #5) the ball, and then rushes in for a quick forehand click.

3) Offensive Shot: The Surprise Backhand Loop

When the opponent sends a slow push to Filus’ backhand, he has time to twiddle paddle and pull off a surprise backhand loop. His loop looks like it’s in slow motion compared to some other offensive players with more offensive equipment, but again the key is the surprise. When the opponent is expecting a simple push or a floater back, a well-placed surprise backhand loop can be incredibly difficult to react to.

4) Offensive Shot: The Forehand Loop

The forehand loop both as an opening and a counter-lop is a standard offensive shot that all choppers have. However, it looks like Filus is able to use his forehand more efficiently and frequently than normal choppers because of his arsenal of other shots. For example, he does not really chop with the forehand but instead uses the shovel (see #5), which has a similar backstroke to a forehand loop. This makes him able to more easily switch to a forehand counter-loop when he sees the opportunity.

In the point shown below, he gets Jang out of position with a fast floater and then hits him with a hard down-the-line counter-loop.

5) Defensive Shot: The Shovel

While Filus usually wins the points off his offensive shots, the defensive shots give him the element of surprise that give his offensive shots the firepower that they have. On the forehand side, Filus essentially never chops. He instead prefers to “shovel” the ball along with his forehand. The drawback of this shot is that it perhaps becomes more difficult for him to sustain a defensive rally than a normal chopper.

However, there appear to be two key benefits. One is that the shovel is slightly faster and gives a sharper tempo contrast with his backhand chops. The second, as mentioned earlier, is that the shovel appears to allow him to more seamlessly integrate offensive forehand loops and even flicks due to their similar backstrokes with the shovel.

This can be seen in the point below, although Filus ends up losing. Another fun nugget in this point is that Filus twiddled to chop with the black inverted side at the beginning of the point.

6) Defensive Shot: The Chop

Last but not least is the shot that Filus is most famous for: the chop. He sometimes twiddles to chop with the black inverted rubber, but he mostly uses it the standard way: an underspin chop with the long pips.

As we mentioned earlier, the chop doesn’t directly win Filus that many points as 72% of his points won against Jang were off offensive shots. In fact, in his match with Jang, Filus lost a majority of the rallies where he was stuck chopping and couldn’t get an offensive shot off.

However, the chop is what unlocks his ability to patiently wait for the chance to unleash all the other shots in his toolkit, so although it doesn’t win him that many points directly, it is the most important shot of Filus’ game and also his signature shot.

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How Korean Teenager Shin Yubin (WR 94) Upset Japanese Star Miu Hirano (WR 12) At WTT Doha

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Shin Yubin (WR 94) continued her sensational run at WTT Star Contender in WTT Doha as she defeated Miu Hirano (WR 12) 11-4, 13-11, 4-11, 11-7 in the round of 16 in a preview of a potential Olympic team semi-final match-up. Shin will play national teammate Jeon Jihee in the quarter-finals.

It is yet another disappointing loss for Hirano in 2021. After a loss to a lower-ranked (granted, Shin is massively underraetd) potential Olympic rival, Hirano’s continued slump has to be raising alarm bells for Japanese team coaches.

The most alarming aspect of this loss for Hirano is that Shin just felt better. Shin dictated the pace of the game and relentlessly attacked Hirano’s elbow, and there seemed little that Hirano could do about it. Shin also appeared to dominate the rallies, and the match ended up being as close as it was largely due to some tricky play by Hirano and what felt like Shin being a bit predictable in game 3.

To get a feel for how concentrated Shin’s attacks to the elbow were, Edges and Nets found that 18 out of 28 (64%) of Shin’s attempted openings were directed at Hirano’s elbow, while only 9 out of 33 (27%) of Hirano’s attempted openings were directed at Shin’s elbow (Hirano mainly attacked both wings). Shin’s mid-rally shots and long serves also targeted Hirano’s elbow.

While the numbers may make it look like Hirano was more aggressive than Shin, they belie the fact that Shin served long roughly twice as often (ten times to five times) than Hirano did in anticipation of a soft opening, which may have reflected her confidence in winning the longer rallies.

Hirano did not help herself in the first game by missing a total of five serve returns and giving a couple of sloppy serves that Shin was able to kill for winners. This included the four early missed serve returns shown below that allowed Shin to build a 7-2 lead and then cruise to a 11-4 victory. In contrast, Shin did not miss a single serve return this game.

The serve return disparity slightly evened out in the second game, and Shin was able to build a 10-7 lead thanks to aggressive play to the elbow like in the clip shown below.

However, Hirano almost stole game two by reaching into her bag of tricks on the serve return: a strawberry to the elbow at 8-10, her first deep push to the backhand of the match at 9-10, and a weird soft floater at 10-11.

After getting her fifth game point at 12-11, Shin apparently had enough with Hirano’s tricks, served a fast long serve to and converted the game point by dominating the ensuing rally.

In the third game, Hirano appeared to better anticipate Shin’s attacks to the elbow as she handled it with a combination of hard step-around forehands and concentrated well-placed blocking. Combined with some additional surprise plays such as another long deep push to Shin’s backhand at 5-3, Hirano was able to build a 8-3 lead and then cruise to a 11-4 victory.

Shin opened up game four with two wide openings to the backhand that Hirano was not expecting. In particular, in the first point shown below, you can see that Hirano’s hand and feet appear to be cheating early towards a step around forehand and she’s completely caught off guard by Shin’s decision.

By diversifying her openings a bit, Shin was able to neutralize Hirano’s anticipation advantage, and in a raw rally, Shin appeared to have the advantage as she walked her way into an 11-7 victory to take the match 3-1. She will face Jeon Jihee in the next round, where she will get the opportunity to stamp herself as the face and future of Korean women’s table tennis.

Shin Yubin dominates the rally en route to her game 4 victory.

The full match is available on WTT/ITTF’s Youtube channel. Full tournament results are available on the WTT website.

Here is an Instagram summary of this post:

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How Mima Ito Defeated Hina Hayata At WTT Doha: A Statistical Analysis Revisited

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Mima Ito defeated Hina Hayata in the finals 4-2 to win the WTT Contender title at WTT Doha. Before the finals started, Edges and Nets wrote a preview that incorporated rudimentary statistical analysis to verify and draw further insights regarding some of our qualitative observations of Ito and Hayata’s match-up at the All Japan National Championships in January.

In this post we revisit the trends we observed in our preview and discuss whether these trends continued to hold in the WTT Contender finals. For a (non-statistical) summary of the finals, please read our recap here. The statistical trends in this match turned out to vary wildly from the All Japan National Championships match. Although this disparity can be partially attributed to uninformative noise present in small sample sizes, we believe that it also partially reflects the dynamic nature of table tennis and how adjustments between matches and even games can wildly swing the nature of a match.

Disentangling these two factors of variation (statistical noise and change in strategy) is an open problem that Edges and Nets is actively exploring. Any suggestions or feedback is welcome.

Ito Dominates On The Third Ball

In our previous post, we noted that Ito had a massive edge in the long rallies, winning a staggering 71% of rallies in which she attempted four or more shots including all six rallies where she attempted five or more shots in the All Japan National Championships match.

Although Ito’s share of total points won rose from 48% to 54%, this time around, Ito only won fifty percent of the long rallies. However, we believe that this discrepancy from Japan can be mainly attributed to the tiny sample size. The number of long rallies dropped by a fair amount; in Japan 14% of the points (for a total of 17 long points) were long rallies and in Qatar that number dropped to 9% (for a total of 10 long points). Hence, if just one or two points had swung the other way (and a couple of the “long rallies” had a fair amount of pushing), the numbers would look more consistent with their Japan match-up.

Unless Hayata suddenly got better at long rallies or Ito suddenly got worse (which is possible if she had a bad night of sleep or something), it is likely that the odds of Ito’s winning a long rally will have stayed relatively similar between January and now. Combining the results of the two recent match-ups, Ito has won 63% of her 27 long rallies against Hayata over the last two months. Our sample size is still quite small and this number may change even more in the future; however, we still feel that Mima Ito is a stronger player in the rallies from watching them play, and physically her lower body looks quite clearly stronger than Hayata’s.

While the change in percentage of long points won by Ito can be attributed to noise and it is possible that the drop in the number of long rallies can as well, we believe that the drop in number of long rallies is due to change in tactics by the players. First, the sample size is larger and thus more robust as the match had 113 points in total. Second, the number of 5-shot, 4-shot, 3-shot, and 2-shot points all decreased and the average rally length (as measured in Mima Ito shot attempts) dropped from 2.3 to 2. As a result the percentage of “one-shot” points that ended in serve, serve return, or third-ball winner by either player rose from 41% to 50%.

Although we previously stated that it may be in Hayata’s interests to lower the length of the rallies, when watching the match it actually felt like Ito was the main one responsible for shortening the rallies as she attempted difficult and aggressive shots with wide angles. This may be reflected in the change in percentage of “one-shot” points won by each player: in their previous match-up in Japan, Ito only won 47% of such points; this time that number jumped to 59%, indicating that she benefited from the shortened points.

Hayata’s Long Serve Management

In an interesting twist, Ito only won 48% of the points in which she served but Hayata only won 40%(!) of the points in which she served. We are not sure what caused this counter-intuitive result.

In our previous post we speculated that Hayata would consider serving more long serves since she actually performed better on her long serves compared to her short serves. It appears Hayata agreed as her percentage of long serves rose from one third to 46%. Her long serves, of which she won 42%, performed slightly better (albeit within the margin of statistical error) than her short serves, of which she only won 39%. Hence, although our judgement must be taken with a massive grain of salt due to small sample size, it appears that Hayata made the correct choice by serving long more often.

We raised the question if it was beneficial for Ito to step around and take Hayata’s serves with her forehand. Ito took 61% (16 out of 26) of Hayata’s long serves with her forehand and won 56% of those point. In comparison, she won six out of the ten long serves she received with her backhand. Hence, with our limited amount of data there is still no evidence that taking the long serve with her forehand or backhand is better.

Did Hayata choke?

We now present a possible explanation for Hayata’s poor performance on her own serve. Did Hayata choke? Meaning, did Hayata play worse than normal because she was nervous? Serves are one of the first things to degrade in quality when a player gets nervous, and she had more than enough reason to be nervous. Although Hayata has played on the big stage before such as in her 2020 All Japan National Championship title run, to the best of our knowledge this is the closest she has ever gotten to winning a major international event.

We know that body-language reading is mostly pseudo-science, but we are going to call upon our resident body language expert anyway to analyze the following clip. This is at the end of game 4 after Ito had narrowed the lead from 10-7 to 10-9 and then called a “covid time-out” where she asked the umpire to wipe the table. Hayata’s face looks frozen in fear and she is completely stiff while Mima Ito is jumping around when the camera pans out (note that Hayata would call time-out and go on to win the game 11-9). This is completely different from when Ito called a covid time-out at 5-3 in the same game (not shown), during which Hayata was also jumping around and keeping herself loose.

Of course, body-language and facial-expression reading is a completely subjective exercise that largely confirms everyone’s own beliefs, and in our recap we already came to the conclusion that Ito was more clutch than Hayata in game 5. It will be interesting to see if we can find a method to quantify clutchness or other soft skills like anticipation. This is largely an open problem across all sports, but we would argue it is particularly important in table tennis, where even a slight change in timing can completely ruin someone’s game.

At the moment, due to the small sample size and the fact that this is a completely new exercise for us, interpreting the limited data appears to be somewhat akin to reading tea leaves, but we hope that the statistics shared in this post provided some additional insight to Mima Ito’s finals victory over Hina Hayata at WTT Contender. Although some people prefer watching many different match-ups, here’s to hoping for another Ito vs Hayata finals in WTT Star Contender so we can do another round of this type of analysis.

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Mima Ito vs Hina Hayata Finals Preview: A Statistical Approach

Not the post you were looking for? A guide to all of Edges and Nets’ coverage of WTT Doha (also known as WTT Middle East Hub and formerly known as ITTF Qatar Open) can be found here.

Mima Ito and Hina Hayata will be facing off in the finals of WTT Contender at WTT Doha shortly. To get ready for the finals match-up, Edges and Nets re-watched their seven game thriller at the All Japan National Championships this January.

We took a new approach of first qualitatively looking for trends and then performing a brief quantitative analysis to confirm our intuition based on manually labeled data. The game went a full seven games for a total of 129 points, giving us a decent sample size. Overall, Ito won 48% of the points despite winning 4-3; this is because she lost a couple games by a wide margin and won all her own games narrowly.

We present two conclusions below. The first conclusion we verify is pretty obvious from watching the tape, but the second insight may be non-obvious without actually looking at the numbers. Although the analysis is primitive, we hope that this post provides a glimpse of a future with more automatically labeled data, from which we may be able to quickly draw further insights from particular match-ups without having to watch too much film.

Longer Rallies Favor Mima Ito

One trend that jumps out when you watch the National Championships matches is that Hina Hayata commonly wins points by exploiting Ito’s height and putting Ito out of position within the first shot or two, and then finishing the point one shot later. However, once Ito is able to get in position in the rally, she is able to return pretty much anything Hayata throws at her.

Ito can handle longer rallies against Hayata very well. Source

To verify this idea, we manually labeled the shot-length and the winner of each rally. Shot length was measured by the number of shots Mima Ito attempted to make (e.g. if Ito misses her third-ball attack or wins the point on her third-ball attack, it is considered a 2-shot rally either way). The reason we count shot attempts and not made is that Ito makes an extra shot when she wins a point, thus biasing the results if we count made shots.

Due to limited sample size, we do not want to perform too fine grained analysis, we divide points into “short” points in which Ito attempted 3 or fewer shots (i.e. the total rally was at most five or six shots depending on who served) and “long” points in which Ito attempted 4 or more shots (i.e. the rallly was at least six or seven shots depending on who served).

87% of the points were considered short points, which makes sense since a lot of table tennis is executing your service and service returns well. In other words, on average there were two and a half long rallies each game. This can absolutely swing the match, as Ito won two games 11-9 and two games 11-8.

Ito only won 44% of the short points, but won a staggering 71% of long points, including all six rallies in which Ito attempted five or more shots. Obviously there is some noise due to small sample size and potential unknown source of bias in our approach, but the results are quite stark.

We thus highlight the importance it is for Hayata to be able to finish the point quickly, although that is obviously easier said than done.

How Should Hayata Manage Her Long Serves?

One of the key challenges in playing Mima Ito is managing long serves. Probably the worst serve one can make when playing Mima Ito is a short serve to her backhand, as that gives her free reign to do whatever combination of banana and strawberry flicks and short and deep pushes that she likes with her short pips. As a result, opponents typically avoid essentially completely avoiding this serve.

The two good serves to Ito are the short serve to the forehand, which prevents her from getting creative with the short pips without getting slightly out of position, and the long serve to the backhand, which forces her to give a predictable and softer return. However, the long serve carries risk, since when Ito anticipates it coming, she can step around for a hard forehand opening against the long serve. Serve too many times long to the backhand, and one may end up simply asking to be killed by her forehand.

It is not obvious just from watching the film which serve is more effective, and it likely varies by match-up and the opponent’s ability to execute each serve. However, we can draw some insight for Hayata by performing quantitative analysis on Hayata’s last match with Ito.

Ito won 52% of the points on her own serve and 44% of the points on serve return, which sounds about reasonable. Hayata served long on roughly one third of her serves, and we can assume that the remaining two-thirds were short and to Ito’s forehand.

The sample size is small as our splits are quite fine-grained, but the results are somewhat interesting. Hayata won 55% of the points in which she served short and to the forehand. On the other hand, she won 60% of the points in which she served long. At least in the previous match, it appears that serving long yielded better results for Hayata than serving short.

It may seem that Hayata should be serving long more often, but we have to consider that the more Hayata uses them then the more Ito will start stepping around, which would decrease the efficacy of the long serve to the backhand but increase the efficacy of the short serve to the forehand.

When looking at the splits between when Ito received the long serve with her forehand or her backhand, this tradeoff appears to emerge: Hayata won seven out of thirteen (54%) of the points that Ito took with her forehand but six out of the nine (67%) points that Ito returned with her backhand.

However, the sample size is tiny, so we cannot draw any strong statistical conclusions; all it would take is one edge ball from Ito to make the efficacy of a serve to the backhand to only be 55%. If the results do hold on larger data, it matches our intuition (and apparently Ito’s since she keeps stepping around) that Ito returns the long serve better with her forehand. If that is the case, left-handed opponents like Hayata may want to consider serving more often from the center of the table in order to land the wide serve to Ito’s backhand.

On the flip side, if after analyzing more data it appears that taking the serve with the forehand and backhand yield similar results, Ito may want to consider if she wants to step around less often, which would presumably allow her to focus more on the short forehand return. That would be a surprising and counter-intuitive result for many including Edges and Nets, but we have seen large-scale quantitative analysis upend common intuition in various other sports.

The data used in the analysis of this post was both primitive and small in scale, but we hope some of the conclusions that we drew offer a glimpse of what can happen in the future given enough well-labeled data. The length of rally, length of serve, and whether a player used forehand or backhand should actually all be pretty easily trackable based on modern AI techniques, and it will be exciting to see what the future holds for quantitative analysis in table tennis.

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