Kazuhiro Kiyohara: A-Rod's Japanese Equal?
The Power Hitter Pantheon: Baseball’s Greatest Home Run Heroes
This project aims to determine the greatest home run hitter of all time by comparing each slugger’s statistics to the average of their era using three formulas. The final adjusted stats will then be used to compare them head-to-head with other all-time greats.
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Kazuhiro Kiyohara will be the next legendary Japanese League slugger examined in this study. For a brief biography of Kiyohara, please click here.
According to Baseball Reference, Kiyohara’s official statistics reveal a total of 527 home runs over 7,865 at-bats resulting in an average of at-bats per home run 14.92 (AB/HR).
Kazuhiro Kiyohara played in the Japanese Pacific League (JPPL) from 1986 to 1996, then in the Japanese Central League (JPCL) from 1997 to 2005. He returned to the JPPL in 2006 and 2008. Kiyohara also competed in the Japanese Western League (JPWL) in 2008.
When aggregating the statistics from each of the seasons Kiyohara competed in, the league totals include 610,415 at-bats and 17,946 home runs, resulting in an average of 34.01 at-bats per home run (AB/HR).
With this data, we can evaluate how Kiyohara’s performance compared to the average Japanese League hitter of his era.
Raw Difference: 19.09
Formula: League Average – Player Career AverageImprovement Factor: 2.28x
Formula: League Average / Player Career AveragePercentage Difference: 56.13%
Formula: (League Average – Player Career Average) / League Average × 100%
Kiyohara’s AB/HR of 14.92 is impressive when stacked against the league average of 34.01. This metric indicates how frequently a player hits a home run per at-bat, so a lower number is better for a slugger.
Kiyohara needed roughly 15 at-bats to hit a home run, while the average player in his era required 34—more than double the at-bats. This shows us that he was a standout power hitter.
The raw difference (19.09) quantifies the gap in efficiency: Kiyohara cleared the league average by a substantial margin. The improvement factor (2.28x) reinforces this—he was more than twice as effective at hitting home runs compared to the typical player. The percentage difference (56.13%) shows that his AB/HR was over 56% better than the league’s, a clear marker of elite performance.
Kazuhiro Kiyohara’s 527 home runs over 7,865 at-bats translate to an outstanding 14.92 AB/HR, far surpassing the league average of 34.01 AB/HR across his career in Japan’s professional leagues.
Kiyohara wasn’t just above average; he was a generational slugger, hitting home runs at more than twice the rate of his peers. This performance cements his legacy as one of Japan’s premier power hitters, thriving across multiple leagues and decades.
In our initial analysis, we examined the careers of Mickey Mantle, Alex Rodriguez, and Joe DiMaggio using our formulas. Following that, we also evaluated the careers of Josh Gibson, Sadaharu Oh, Buck Leonard, Tetsuharu Kawakami, Mule Suttles, Noboru Aota, Oscar Charleston, Katsuya Nomura, Turkey Stearnes, Makoto Kozuru, Willie Wells, Hiromitsu Ochiai, Wilson Redus, Kazuhiro Yamauchi, Dewey Creacy, Hiromitsu Kadota, Edgar Wesley, Koji Yamamoto, Jud Wilson, Fumio Fujimura, and John Beckwith.
Now, let's compare Kiyohara’s career statistics against these baseball legends to gain a clearer perspective on how he stacks up.
Kiyohara’s 19.09 Raw Difference, 2.28x Improvement Factor, and 56.13% Percentage Difference mark him as a standout, even among this select group of sluggers whose stats orbit his own.
Alex Rodriguez (16.24, 2.07x, 51.69%):
Kiyohara’s 19.09 tops Rodriguez’s 16.24, and 2.28x outshines 2.07x. The 56.13% vs. 51.69% difference further tilts the scales in his favor.
Koji Yamamoto (16.11, 2.07x, 51.75%):
Kiyohara’s 19.09 raw difference outpaces Yamamoto’s 16.11 by nearly 3 points, and his 2.28x factor tops 2.07x. The 56.13% vs. 51.75% gap shows Kiyohara’s superior efficiency in clearing the league average.
Hiromitsu Ochiai (16.88, 2.13x, 53.03%):
Kiyohara edges Ochiai’s 16.88 with 19.09, and his 2.28x factor beats 2.13x. His 56.13% percentage difference also surpasses 53.03%, a clear win in power impact.
Hiromitsu Kadota (15.22, 1.97x, 49.32%):
Kiyohara dominates here—19.09 over 15.22, 2.28x over 1.97x, and 56.13% over 49.32%.
In this tight orbit, Kiyohara consistently rises to the top. His 2.28x improvement factor is the highest, and his 56.13% percentage difference leads the pack. The raw difference of 19.09 is a notch above all four peers, signaling that Kiyohara wasn’t just in their league—he was the pacesetter.
Kazuhiro Kiyohara stands as the undisputed champion of his statistical orbit, his 19.09 raw difference, 2.28x improvement factor, and 56.13% percentage difference eclipsing the likes of Koji Yamamoto, Hiromitsu Ochiai, Hiromitsu Kadota, and Alex Rodriguez.
In this razor-tight group of sluggers, Kiyohara’s bat roared loudest, outdistancing Yamamoto’s 16.11, Ochiai’s 16.88, Kadota’s 15.22, and Rodriguez’s 16.24 in raw impact, while his 2.28x factor and 56.13% edge set a benchmark they couldn’t touch.
Interesting thread here. His career essentially paralleled that of Bonds as his MLB counterpart. The Youmiri Giants are essentially the "sister" (well brother) team to the SF Giants. Wonder why he didn't make the jump to MLB?