Masahiro Tanaka returned to Japan a year ago, ostensibly so he could contribute toward a pennant for the Rakuten Eagles 10 years after the Sendai-based club’s area was ravaged by an earthquake and tsunami that killed nearly 20,000 with about 2,500 still missing.
And though it didn’t quite pan out that way with the Eagles finishing third and getting eliminated in the first stage of the playoffs, Rakuten did manage to make the playoffs. Carrying the weight of the world on their shoulders in 2011, they finished fifth.
A lot of you know the Tanaka story. A nationally known high school star who was selected by four teams in Nippon Professional Baseball’s 2006 draft. From the middle of the 2012 season through 2013, he won 28 regular season games during which he posted a quality start every time out. The Eagles won the pennant and the Japan Series, despite Tanaka losing his only game in over a year in Japan Series Game 6.
He was a unanimous selection for Pacific League MVP and then moved to New York, on a personally chartered 787, to play for the Yankees.
What you might not have considered, and what his most famous season made me forget, was that 2013 was probably Tanaka’s second best season.
In 2011, in a season that started with the Eagles’ home park out of commission due to earthquake damage, Tanaka had arguably his best season ever.
I’m now in the process of reworking my Bill James Win Shares calculations for Japanese pro baseball, starting with a more detailed analysis of park adjustments to better account for the annual grab bag of neutral parks teams play at.
The first set I’ve done is from 2007 to 2021, and I was surprised to see Tanaka getting 30 win shares in 2011 and 27 in 2013. In my previous calculations, his 2013 season led 27 to 23, but there were some errors in the process — the Eagles’ seven ties, worth 10.5 more win shares, were missing from 2011.
Tanaka went 19-5 in 2011 with 14 complete games, including six shutouts and pitched a career-high 226-1/3 innings with a career-high 241 strikeouts and a career-low35 runs allowed and 1.27 ERA.
In 2013, he went 24-0 with one save and eight complete games, including two shutouts, in 212 innings during which he struck out 183 batters and also allowed 35 runs and a 1.27 ERA.
The difference
The Eagles won 66 games and tied seven in 2011, for a total of 208.5 win shares. Their 82 wins and three ties in 2013 were worth 250.5. The biggest singled difference between the two Eagles teams was essentially their ability to score runs.
The 2011 offense scored 167 marginal runs — above a calculated minimum based on league averages and park adjustments. The 2013 crew scored 324. the 2013 pitching and defense was better, but nothing compared to how much better the offense got.
The formulas credits the 2011 pitching staff with 29.21 wins, and the 2013 staff with 29.16,
The 2011 team had 193-1/3 innings pitched by players whose total performances were so poor that they cannot be given any share of credit for the team’s wins. In 2013, that total was 133 innings.
Win Shares divides up the team’s pitching credit among a teams pitchers based on how many runs they save, their wins, saves, losses and holds, how effective they are in relief, and their three “true outcomes.” James calculations gives Tanaka 99 “claim points” for 2011 and 119.7 for 2013, reflecting a better-looking stat line.
The rest of the Eagles’ staff however, was quite a bit weaker in 2011, despite the system crediting them with about one tenth of a win more than in 2013. The result is that Tanaka’s 33.7 percent of the 2011 team’s pitchers share surpasses his 29.2 percent of the 2013 team’s pitching total.
Although the Eagles finished fifth, Tanaka finished second in the PL MVP voting that year with 43 first-place votes and 414 points. Seiichi Uchikawa of the PL champion Hawks won with 120 first-place votes and 757 points.
Here are the pitchers with the top 10 seasons according to Bill James Win Shares since 2007 — because that’s the year I have data at hand for now.
| Name | Year | Team | Win Shares |
|---|---|---|---|
| Masahiro Tanaka | 2011 | Eagles | 30 |
| Masahiro Tanaka | 2013 | Eagles | 27 |
| Yu Darvish | 2008 | Fighters | 24 |
| Tomoyuki Sugano | 2017 | Giants | 24 |
| Yu Darvish | 2011 | Fighters | 24 |
| Yu Darvish | 2007 | Fighters | 23 |
| Masahiro Tanaka | 2009 | Eagles | 22 |
| Yoshinobu Yamamoto | 2021 | Buffaloes | 22 |
| Hisashi Iwakuma | 2008 | Eagles | 22 |
| Tomoyuki Sugano | 2018 | Giants | 21 |
| Kyuji Fujikawa | 2007 | Tigers | 21 |
| Kenta Maeda | 2010 | Carp | 21 |
| Chihiro Kaneko | 2013 | Buffaloes | 21 |
| Yu Darvish | 2010 | Fighters | 21 |
