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Analyzing Jeon Jihee’s Evolving Service Strategy Against Mima Ito

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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.

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

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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 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 Wins WTT Doha Event With 4-2 Finals Win Over Hina Hayata

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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.

For more coverage of the WTT Contender women’s singles finals, check out our preview and our post-game analysis.

Tied 2-2 in games, Mima Ito (WR 3) and Hina Hayata (WR 29) both reached into their bag of tricks as Ito eked out a gutsy 11-9 win in a pivotal game 5 en route to a 11-9, 11-8, 6-11, 9-11, 11-9, 11-6 finals victory over Hayata. With the win Ito, has captured the first ever World Table Tennis (i.e. rebranded ITTF) Title in the WTT Contender Event at WTT Doha. The qualification draw of WTT Star Contender, the second and more prestigious event at WTT Doha, is already underway and will be ongoing throughout the week.

The victory is slightly dimmed due to the withdrawal of Sun Yingsha and Liu Shiwen and general lack of star-power among Ito’s opponents (none of her opponents were in the top 20 although Hayata likely deserves to be in it). However, Ito was still able to make a small statement; while all the other top seeds in the event were getting upset left and right, Ito was able to stay steady take care of business. If everyone has similar showings in WTT Star Contender event, Ito can make the case for why she is arguably the ONLY serious threat to Chinese supremacy at the Tokyo Olympics.

Game 1

Ito opened the match very aggressively, which initially cost her as she missed several aggressive forehand smashes to go down 7-3. However, her shots suddenly started landing and went on a 8-2 run to take the game 11-9. Save for a net ball when down 7-4 (which itself was in the middle of an offensive rally), all of Ito’s last eight points were won off of aggressive wide openings or ambitious forehand smashes. Both the points she lost were a result of her missing her own forehand smash.

Game 2

Ito’s aggressive style carried into game 2, but thanks to a couple early service and return errors and a missed smash, Hayata was able to open up an early 5-3 lead that could have been larger if not for a couple of her own easier backhand errors.

Ito then won four points in a row to take a 7-5 lead. Two of these points followed the same strategy of allowing Hayata to open with her backhand against a short ball to the center and then smashing the ball back hard for the winner after anticipating its location.

Ito would use the same play again at 8-7 to maintain a 9-7 lead. Ito then surprised Hayata with a short push; Hayata rushed when stepping in and flicked the ball into the net, giving Ito three game points at 10-7. Ito missed a forehand smash to cut it to 10-8, but Hayata then missed a forehand flick on the serve return to lose the game 11-8.

Game 3

Similar to game 1, Ito continued to be aggressive and go for hard and wide forehand smashes, but missed several of them. Hayata also added some extra twists to her short game including a half-long push at 3-2 and a surprise forehand flick at 6-3 that, combined with Ito’s errors, were enough for Hayata to go up 9-3.

Ito was able to win two points on her own serve to cut it to 9-5. Hayata then served long to Ito’s elbow but missed the block when Ito stepped around to smash it to her backhand. On the very next point, Hayata trusted her long serve and anticipation again as she served a long serve again to Ito’s elbow, but this time a little further to the backhand, and when Ito stepped around and hit it to Hayata’s backhand, Hayata was ready for a wide block to Ito’s forehand for the winner.

Ito was able to catch Hayata with a long serve on the next point, but Hayata’s surprised return carried some weird spin and neither player seemed to know what was on the ball for a couple shots before Ito went for the smash and hit it out the table, giving game 3 to Hayata 11-6.

Game 4

Hayata showed some great anticipation and killed several of Ito’s openings as she built a 6-3 lead. However, Hayata then missed her own serve, lost a weird point after a net ball, and then lost a great rally to level it at 6-6. However, Hayata was unfazed as she continued to show great anticipation and smack down many of Ito’s openings and fool Ito with her long serves to cruise to an 10-7 lead.

However, a winning serve return from Ito and a missed serve return by Hayata cut the lead to 10-9. Ito calmly asked for her second “covid timeout” of a game (i.e. where a player effectively gets an extra mini-break by asking the umpire to “wipe down” the table), and what appeared to be a rattled Hayata then called a real timeout.

Hayata then opened with a chiquita to Ito’s wide backhand and then hit a hard wide backhand winner against the soft return to take the game 11-9.

Game 5

Neither player was able to take control the pace of the game like Ito in games 1 and 2 or Hayata in games 3 and 4. Ito had the slight edge in rallies, allowing her to build 8-6 lead. It was around at this point that both players appeared to bust out their bags of tricks.

Hayata won a point off a tricky half-long serve, and Ito took the next point with a short, high, and very strange chop block that Hayata hit into the net. Hayata then won the next point with a strawberry flick to cut the lead to 9-8. Each player then won a point off the third ball following great anticipation, resulting in a 10-9 lead for Ito with Hayata to serve. Ito then opted for a short push instead of the backhand flick that Hayata was expecting on the serve return, and Hayata missed the following push as Ito eked out a clutch 11-9 win in a pivotal game 5.

Game 6

Game 6 got off to a strange start. Hayata first won a beautiful rally before missing her own serve to level it at 1-1. Ito then caught a net ball and a pretty wide block to take a 3-1 lead. Hayata then proceeded to serve long on all four of her next four serves and lost all four points. However, Ito returned the favor by losing four straight of her own serves, including a missed serve.

Hayata was able to get narrow the lead one more point to 7-6 with a deep push to Ito’s backhand before dropping the next point to g o down 8-6. Hayta then missed a serve return and then lost the next point after Ito got a net ball, giving Ito quadruple match point at 10-6. Hayata’s shoulders slumped in frustration, and although it looked like she had gathered herself together for the next point, her serve was a bit high, and Ito killed the serve with a wide punch to Hayata’s forehand.

This sequence capped off a 5-0 streak for Ito in what was otherwise a close and unpredictable game. She thus took the match 4-2, and with it, the first ever WTT title (WTT Macau does not count because the rules were a complete gimmick).

Notes

On the men’s singles side, Dimitrij Ovtcharov captured the title with a 4-1 win over Lin Yun-Ju.

Ito missed three of her own serves and Hayata missed two. It’s unclear why whether the large number of missed serves was due to nervousness, rustiness, or a change in routine due to covid restrictions (e.g. no touching the table).

Either Ito sweats a lot or she really likes making use of the so-called covid timeout.

Edges and Net previously released a rudimentary statistical analysis of the Hayata vs Ito match-up. We will shortly follow up on how these trends held at WTT Doha in an upcoming post. Stay tuned!

The outfits this time were significantly better than whatever they were wearing at the All Japan National Championships in January, which can be seen in our Instagram post below. Between these National Championship outfits and Harimoto’s tendency to dress like a fruit with his monochromatic color schemes, Edges and Nets is not a huge fan of Team Japan’s fashion choice.

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Mima Ito vs Hina Hayata Finals Preview: A Statistical Approach

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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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Unless stated otherwise, all images and footage in this post can respectively be found on ITTF’s Flickr page and ITTF’s Youtube Channel.