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Genda and NPB’s best

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It took a while for the Japanese language media to catch on to Sosuke Genda’s shortstop fielding records in 2018 because fielding data in Japan is considered even more esoteric than it is in the States, and I’m referring to just the basics, put outs, assists, errors, double plays, fielding percentage.

There’s really nowhere to scan a publicly available database and find out who had the most assists or putouts in an NPB season or in their career. Things are getting better, but it’s still to quote Mr. Spock, “Stone knives and bearskins.”

The data is out there, it’s just inaccessible. This year, NPB’s website (the Japanese language version) did us the great service of posting a player page for every past NPB player. Of course, this includes batting and pitching. When NPB was publishing its encyclopedia, it did not include fielding records.

So here are the top 10 Japanese pro baseball seasons by a shortstop ranked in terms of total double plays and then assists

YearLeagueTeamName RGPOAEDPField
2018PLLionsSosuke Genda14327152611112.986
1963PLHawksKenji Koike14729549323111.972
2008CLTigersTakashi Toritani14426347615107.980
1985CLCarpYoshihiko Takahashi13023946816107.978
1998PLMarinesMakoto Kosaka12323641716106.976
1981PLBravesKeijiro Yumioka13021044917104.975
1964PLHawksKenji Koike14928949836103.956
2007CLCarpEishin Soyogi13523143913103.981
1991CLSwallowsTakahiro Ikeyama1322704124101.994
2006CLTigersTakashi Toritani14621349021100.971
2001CLBayStarsTakuro Ishii14025241712100.982
2016PLFightersTakuya Nakashima14321944714100.979

Top 10 NPB shortstop seasons ranked by total assists

YearLeagueTeamNameGPOAEDPField
2018PLLionsSosuke Genda143271526111120.986
19481LDragonsKiyoshi Sugiura13726850245900.945
1954PLBuffaloesTakeshi Suzuki13221950144680.942
1964PLHawksKenji Koike149289498361030.956
1963PLHawksKenji Koike147295493231110.972
2001PLMarinesMakoto Kosaka14025249216990.979
2006CLTigersTakashi Toritani146213490211000.971
2000PLMarinesMakoto Kosaka13522648911980.985
2003PLMarinesMakoto Kosaka1342264838860.989
2017PLLionsSosuke Genda14322848121890.971

Other than Genda, the big name on this list is Kenji Koike of the Nankai Hawks. Bill James’ win shares credits him with having four of the six most valuable defensive seasons at shortstop in the history of pro baseball in Japan. Koike’s rival for the title of Japan’s greatest shortstop is Hall of Famer Yoshio Yoshida, who had more career value at the position but did not reach the amazing peaks Koike did.

Genda’s 2018 season ranks 20th. A lot of that has to do with context. Genda is an amazing fielder, but NPB’s defensive standards are now remarkably high.

Win shares rates former Marines shortstop Makoto Kosaka as the best to play the position in the past 25 years and he is the only player in the last 50 years to have a season value ranked in the top 10.

For non win shares people, be warned that while win shares does give credit to various performance data, it is heavily weighted toward the context in which those data are compiled. It matters how many games your team wins, how good the team’s fielding is in relation to its batting and pitching, and how good the overall team defensive numbers at each position compare to the league norms. Good teams have more credit to pass around than weak teams and players who perform above the league’s norms will have a larger share of his team’s defensive credit than those who are below average and so on.

I’ve tried to post output from my database here in large files that can easily be read, but I’m not a database person or much of a coder, so that technology escapes me. I hope to remedy that by posting files of the top 20 in each defensive category by position on the data page, at least that way readers can monitor what the different records are.

Commentary, Paid Content, Research

Whys, wherefores and Win Shares

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So, how many win shares was that Neftali Soto home run worth, smart guy?

今年のＭＶＰ、最優秀新人選手、ベストナインの投票について各ＮＰＢ選手のWin Shares（ウィン・シェア）を計算しました。Win Sharesの日本語の説明はこちです。

I’ve written in the past that I use Bill James’ Win Shares methodology to generate my short list of candidates for my postseason award votes, the MVP, Rookie of the Year, Best Nine and Gold Gloves. It’s not an easy system to use, but has two very attractive features.

  1. The wins attributed to a team’s players cannot exceed the number of wins the team achieves.
  2. Because it works from the concepts of league defensive norms at different positions rather than raw fielding numbers — that are often skewed toward poor teams that have allowed more base runners.




The system also has many inherent flaws particularly the lack of loss shares — something James is ostensibly still working on — to account for defensive responsibilities and playing time.  The proposed new system would give every player a win-loss record, where the current system has to make do with a single figure.

This comes into play when you compare, for example, two DeNA BayStars outfielders, Yoshitomo Tsutsugo and Neftali Soto. Win Shares assigns Tsutsugo, the Japan cleanup hitter, with 22.5 percent of the club’s offense win contribution, and Soto — who also hit 38 home runs but in just five months and who was vastly more productive with runners on base and in scoring position — with 21.3 percent.

But here’s the catch, Soto made 7.7 percent of the BayStars’ batting outs, while Tsutsugo made 9.4 percent, a 20 percent increase. If we were assign the two loss shares to go with their win shares, I’m guessing Tsutsugo would be 22-11, while Soto was 19-7 and probably more valuable.

This sometimes creates disconnects for a variety of reasons. Two players with identical production on teams playing in similar offensive contexts can have quite different win share totals. If one team wins more games than its totals of runs and runs allowed would suggest, that team will have more wins to divide up among its players than a team that got fewer wins than expected.

A surprise from this year’s win shares calculations involved Yakult Swallows closer Taichi Ishiyama. He finished second in pitching win shares in the Central League behind Tomoyuki Sugano. How could that be?

Because the Swallows’ parks this year gave them the highest run adjustment — meaning runs were easier to come by in their games than in any other team’s in Japan this year — Yakult’s 658 runs scored — the second-highest CL total was not nearly as impressive as their CL-worst 665 runs allowed. Win Shares estimates the Swallows scored 297 runs more than the worst offense imaginable would score, but saved 416 runs more than the worst possible pitching and defense would allow.

That gives a huge amount of the credit for their 75-win total to the pitching and defense, and since the Swallows also won more games than expected given the number of runs scored and allowed — it means pitchers who excelled for them this season could potentially be credited with contributing to more wins than expected.



According to Win Shares, the top 10 CL pitchers this season were, in order:

1. Tomoyuki Sugano,
2. Taichi Ishiyama
3. Katsuki Azuma
4. Daichi Osera
5. Yasuaki Yamasaki
6. Onelki Garcia
7. David Buchanan
8. Yasuhiro Ogawa
9. Randy Messenger
10. Kris Johnson

I would never argue that’s right, but there are bits of truth that the system can illuminate.