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

Top 10 NPB shortstop seasons ranked by total assists

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.