The Pacific League has now won the last seven Japan Series and has a .532 interleague winning percentage. People have attributed the gap to more hard-throwing pitchers in the PL, or to larger ballparks and the DH that helped that league be better at developing pitchers.

But two years ago, former Giants pitcher Scott Mathieson attributed it to the drafting philosophies of the two leagues, that the six Central League teams have shown more inclination to draft “baseball instinct” over physical tools.

Is it the draft?

This study won’t address that question, but it does ask whether one league has had an advantage in the draft and its Siamese twin, player development.

The answer is yes, and no one will be surprised to find that the PL has had a clear edge in this area.

To answer this and another question for another study, I created a database with the draft ranking of every signed player in Nippon Professional Baseball’s annual autumn amateur draft. For each player there is also a corresponding measure of career value, using Bill James’ win shares as I have adopted them to fit NPB.

Since we’re more interested in the CL’s current troubles, I looked at the drafts since 2000 and broke them down into two, ten-year periods. Interestingly enough, the top four players drafted since 1999 all were by CL teams: Shinnosuke Abe, Takashi Toritani, Hayato Sakamoto and Norichika Aoki.

The win share totals include those from the major leagues.

Players drafted from 1999 to 2008

The results of the second group are of course much smaller since many of these players have had little or no chance to impact the score, so it’s probably too early to think the PL’s edge is shrinking.

Players drafted from 2009 to 2018

The good and the bad

Here are the breakdowns of the return on amateur talent by team draft. Just a note, the three players still active from the 1998 draft, Kosuke Fukudome, Kyuji Fujikawa and Daisuke Matsuzaka, are not included in the study.

The first PL table includes the Kintetsu Buffaloes in the Rakuten Eagles, since the Eagles are the team that took Kintetsu’s place in the league.

In both the 1999 to 2008 group and the 2009 to 2018 group, the CL placed just two teams in the top six. Another interesting point is that while the Yomiuri Giants have invested heavily in developmental players, essentially the team’s return came from two guys who are both retired, reliever Tetsuya Yamaguchi and center fielder Tetsuya Matsumoto, who both won CL Rookie of the Year Awards over a decade ago.

Central League drafts 1999 to 2008

Pacific League drafts 1999 to 2008

Central League drafts 2009 to 2018

Pacific League drafts 2009 to 2018