Who has been the most dominant pitcher in Nippon Professional Baseball history, and how would one go about answering this question?
It’s not an easy answer, since baseball careers represent multiple dimensions: performance over a career, performance within seasons and performance in individual games of greater or lesser import.
Therefore, there is no single objective answer, but I’ll give it my best shot.
While researching a story for Japan’s Slugger Magazine, I spoke to MLB scouts about the next crop of pitchers who might move to MLB, and they all referred to the difficulty in identifying a Japanese pitcher to follow in the footsteps of Yoshinobu Yamamoto.
I casually mentioned my belief that Yamamoto might have been the most dominant pitcher in the history of Japanese pro baseball without any objective evidence to back it up. In one sense, I believe I was spot on, and had his career continued in Japan, he certainly would have had a chance to turn in the greatest career in NPB history.
In 2013, I had a similar conversation with a co-worker at Kyodo News when I suggested that Masahiro Tanaka’s 2013 was the greatest pitching performance in Japanese history, better than Hall of Famer Kazuhisa Inao’s 1961 season, when the big guy went 42-14 with a 1.69 ERA in a career-high 404 innings.
If one looks to measure dominance, one really needs to know what one’s peers accomplish within a similar context.
That’s because the conditions are different every single year, and that evaluating Inao’s achievement in 1961, requires comparing him to other pitchers that year. Among pitchers in 1961 who threw 130-plus innings, Inao was 3.1 standard deviations above the mean in win shares per game played by his team.
That same year, the Dragons’ Hiroshi Gondo went 35-19 with a 1.70 ERA in 429-1/3 innings, while the Flyers’ Masayuki Dobashi was 30-16 with a 1.90 ERA in 393 innings.
The point is not to downplay Inao’s accomplishments but to recognize that Tanaka in 2013 was even more of an outlier.
That was the second most dominant season in Inao’s career relative to his peers, and tied him for the 10th best in NPB history. The single most dominant season this method found was Hall of Famer Masaichi Kaneda’s 1963 campaign for the Kokutetsu Swallows, when he went 30-17 with a 1.98 ERA that was 3.7 standard deviations above the mean.
Tanaka’s 24-0, 1.27 ERA season in 2013 for the Rakuten Eagles ranks second in history behind Kaneda’s best.
Because his Japan career has no post-prime downward slope yet, and ignoring career longevity, Yamamoto currently ranks No. 1 among pitchers with four-plus 130-inning seasons, averaging 2.48 SDs above the mean. No other pitcher is above 2.0.
Here are the top-10 most dominant single seasons by a pitcher in NPB history:
Pitcher | SDs above mean | Year |
---|---|---|
Masaichi Kaneda | 3.66 | 1963 |
Masahiro Tanaka | 3.64 | 2013 |
Gene Bacque | 3.47 | 1964 |
Shigeru Sugishita | 3.44 | 1954 |
Isao Ikda | 3.31 | 1980 |
Minoru Murayama | 3.29 | 1966 |
Kazuhisa Inao | 3.29 | 1957 |
Yoshinobu Yamamoto | 3.26 | 2021 |
Masahiro Tanaka | 3.22 | 2011 |
Jyuzo Sanada | 3.11 | 1950 |
Here are the best three-season stretches in NPB history:
Pitcher | avg | 1st year | 3Rd year |
---|---|---|---|
Tomoyuki Sugano | 2.957 | 2016 | 2018 |
Yoshinobu Yamamoto | 2.860 | 2021 | 2023 |
Kazuhisa Inao | 2.760 | 1957 | 1959 |
Masahiro Tanaka | 2.687 | 2011 | 2013 |
Masaichi Kaneda | 2.680 | 1962 | 1964 |
Masaichi Kaneda | 2.667 | 1956 | 1958 |
Keishi Suzuki | 2.567 | 1967 | 1969 |
Keishi Suzuki | 2.513 | 1968 | 1970 |
Jiro Noguchi | 2.500 | 1940 | 1942 |
Masaichi Kaneda | 2.493 | 1955 | 1957 |
Tomoyuki Sugano | 2.430 | 2015 | 2017 |
Jiro Noguchi | 2.430 | 1939 | 1941 |
Masaichi Kaneda | 2.427 | 1961 | 1963 |
Yu Darvish | 2.420 | 2007 | 2009 |