Japanese baseball performance should, in theory, be as translatable as

performance from any baseball league in the United States. The process has

had its challenges, though: the data is not as easy to find, and much of

what is available is in a language and a character set that I can’t read. (I

still don’t have complete data for 1996).

More serious a problem is the small number of players moving between Japan

and the United States. The Translations system depends on being able to set

a difficulty level for each league. To do that, I need to have a sizable

group of players who have played in both the leagues I am testing and in

leagues whose difficulty level I already know. Every player who played in

both leagues needs to be compared to the league average; if, as a group, one

set is league average, and the second set is 10% above average, you can

assume that the second league is 10% worse that the first league.

With the Japanese leagues, there really haven’t been enough comparisons to

get a firm grip on the appropriate difficulty level, especially since almost

all the comparisons were of players who went from the U.S. to Japan, and not

from Japan to the U.S..

Last year, for the first time, there were more common plate appearances from

the prior year moving from Japan to the U.S. than vice versa. (A common

plate appearance is the lesser of a player’s plate appearances in League 1

and in League 2; it is what I use to ensure that a given player is always

weighted equally.) Alex Ramirez was the only player who went to Japan

last year to log more than 100 CPA, while five players–Ichiro

Suzuki, Tsuyoshi Shinjo, Orlando Merced, Tony

Fernandez, and Lou Merloni–came to the U.S. and reached that

standard.

Using one-year differences, here’s how the difficulty ratings for Japan

shape up:



Lge1



Lge2



CPA



EqA1



EqA2



Diffic



Most CPA



2000 Jp



2001 Mj



1252



.301



.273



.907



Ichiro Suzuki, Tsuyoshi Shinjo, Orlando Merced



1999 Jp



2000 Mj



288



.286



.244



.853



Mark Smith



1998 Jp



1999 Mj



174



.253



.277



1.095



Dave Hansen



1997 Jp



1998 Mj



54



.325



.207



.637



Jim Tatum



1995 Jp



1996 Mj



1149



.294



.283



.963



Julio Franco, Pete Incaviglia, Kevin Mitchell



1994 Jp



1995 Mj



589



.268



.253



.944



Mike Pagliarulo, Dion James, Jerald Clark



2001 Jp



2000 Mj



674



.278



.255



.917



Alex Ramirez



2000 Jp



1999 Mj



1893



.281



.267



.950



Tony Fernandez, Brian Banks, Dave Nilsson, Reggie Jefferson



1999 Jp



1998 Mj



979



.282



.236



.837



Mike Blowers, Melvin Nieves, Robert Perez, Mark Smith



1998 Jp



1997 Mj



1218



.277



.261



.942



Julio Franco, Mariano Duncan, Dave Hansen



1997 Jp



1996 Mj



1254



.291



.263



.904



Mark Carreon, Leo Gomez, Bill Selby



1995 Jp



1994 Mj



2146



.295



.296



1.003



Julio Franco, Darrin Jackson, Shane Mack, Troy Neel



1994 Jp



1993 Mj



2483



.270



.266



.985



Kevin Reimer, Jerald Clark, Dan Gladden, Dion James



weighted average



14153





.946





You can do the same analysis with Triple-A players. In fact, it is better to

use Triple-A players: the Japanese leagues have generally taken players who

were stuck in the minors, guys who tend to end up in Triple-A again even if

they come back. There have been far more common PA between Japan and

Triple-A than there have been between Japan and the majors.



Lge1



Lge2



CPA



EqA1



EqA2



Diffic



Most CPA



2000 Jp



2001 AAA



2131



.265



.283



1.068



Tony Tarasco, Andy Abad, Jason Hardtke



1999 Jp



2000 AAA



1042



.293



.300



1.024



Mark Johnson, Robert Perez, Alan Zinter



1998 Jp



1999 AAA



1033



.266



.287



1.079



Jerry Brooks, Alonzo Powell, Ryan Thompson



1997 Jp



1998 AAA



826



.244



.273



1.119



Phil Hiatt, Jason Thompson, Bill Selby



1995 Jp



1996 AAA



1233



.270



.301



1.115



Lee Stevens, Kevin Reimer, Tim McIntosh



1994 Jp



1995 AAA



1529



.242



.273



1.128



Rick Schu, Brian Traxler, Rob Deer



2001 Jp



2000 AAA



3129



.278



.308



1.108



Scott McClain, Pedro Valdes, David Doster, Ozzie Timmons



2000 Jp



1999 AAA



2005



.258



.303



1.174



Tony Tarasco, Andy Abad, Jason Hardtke, Jeff Barry



1999 Jp



1998 AAA



2997



.292



.321



1.099



Roberto Petagine, Mark Johnson, Micah Franklin, Alex Diaz



1998 Jp



1997 AAA



611



.267



.324



1.213



Eric Anthony, Harvey Pulliam



1997 Jp



1996 AAA



3281



.281



.308



1.096



Nigel Wilson, Jerry Brooks, Jason Thompson, Dwayne Hosey



1995 Jp



1994 AAA



2157



.286



.312



1.091



Glenn Davis, Rob Ducey, Scott Coolbaugh, Doug Jennings



1994 Jp



1993 AAA



1135



.277



.287



1.036



Brian Traxler, Lee Stevens, Hensley Meulens



weighted average



23109





1.102





In Baseball Prospectus 2001, I wrote that the difficulty level of

Japan was "about even with the Triple-A leagues." Looking at it

more comprehensively–I was basing my assessment on a scattering of players,

rather than off a full list of Japanese player data–that was a silly thing

to say, as the Japanese leagues have clearly and consistently rated as

tougher than the American Triple-A leagues. Every case from the 1990s shows

that players do worse as a CPA-weighted-average group in Japan than they do

in Triple-A, and by a considerable margin. The Triple-A/majors multiplier is

.860; if the transitive property holds, then Japanese EqA is worth about

.948 of a major-league EqA, which conveniently enough is almost identical to

what we got from major leaguers.

You can, of course, do the same thing with pitchers. The total ERA ratios

for those come out as:



Triple-A weighted average: 17991 IP 1.154 Major league weighted average 7178 IP .903



Remember, though, this is in runs, and runs are proportional to EqA to the

2.5 power. These ratios, in EqA terms, are the same as 1.058 and .960. The

1.058 between Triple-A and Japan is equivalent to a .910 ratio between Japan

and the majors. So we have, all in EqA and major-league terms:



Hitting Triple-A to Japan .948 Hitting Major Leagues to Japan .946 Pitching Triple-A to Japan .910 Pitching Major Leagues to Japan .960



The mean of these values is .941.

For perspective, the Federal League, compared to the AL and NL of the

mid-teens, rated as .93 and .95 in its two years of existence. It is

considered a major league. The American Association of the 1880s lasted nine

years; compared to the NL of the same era, it rated as low as .78 (in its

debut year), and eventually got as high as .94. The AA is considered a major

league. The Union Association only existed for one year, 1884, and it rated

at .71, about the same as the present Midwest League. It is considered, by

Major League Baseball, to have been a major league (a very bad decision, in

my opinion; the St. Louis team, led by Fred Dunlap, was major-league

quality, but no other team in the league was.) The Players League of 1890

actually rated as stronger than the NL, with a 1.01 rating. The American

League of 1901, when Nap Lajoie hit .426, has a rating of .93.

The Japanese leagues meet or beat all of them. By historical standards, the

present-day Central and Pacific Leagues are fully deserving of the

"major league" label.

Japanese Ballparks

We’ve all heard about the tiny little Japanese ballparks, and the impact

they have on the home-run totals of visiting Americans. That isn’t so true

anymore. A wave of stadium building swept through Japan over the last 15

years; all six stadiums in the Pacific League, for instance, have been built

or remodeled since 1988, although the Central league still has two parks

from the 1920s. The remade stadiums are only slightly smaller than their

American counterparts.

At least, that’s true of the primary stadium for each team. Japanese teams

apparently schedule a number of games away from their nominal home stadium.

Of the 70 home games played by the champion Yakult Swallows in 2001, only 59

were played in their Jingu Stadium home. They played three games in Fukuoka

(home of the Pacific League’s Daiei Hawks; there is no interleague play in

Japan, so it’s like having the Yankees play in Shea Stadium), two in Chiba

Marine Stadium (home of the Chiba Lotte Marines), two in Sapporo, two in

Morioka, one in Nagano, and one in Sendai. I have no idea how large these

outside stadiums are.

Of course, size isn’t the only issue for how a park plays. From looking at

their dimensions, I expected the two 1920s parks–Yakult’s Jingu Stadium and

Hanshin’s Koshien Stadium–to be wildly divergent. Jingu has very small

dimensions, while Koshien is a lot more spacious. Americans playing for

Yakult have done better than expected; Americans playing for Hanshin have

done worse. I fully expected Yakult to have a Coors-like park factor, and

for Hanshin to look like the old Astrodome.

The game-by-game records for the last two years were available online, so I

compiled park factors for Japan exactly the way I do for American teams.

What I thought would show up didn’t happen at all.

The parks:



Team



2000 PF



2001 PF



Comments



Chunichi Dragons



976



888





Hanshin Tigers



959



978



Large dimensions



Hiroshima Toyo Carp



1074



1004





Yakult Swallows



1027



1009



Very small dimensions



Yokohama Bay Stars



1043



1031





Yomiuri (Tokyo) Giants



952



1081





Chiba Lotte Marines



973



1044





Fukuoka Daiei Hawks



971



969





Nippon Ham (Tokyo) Fighters



1034



1107



Shares with Yomiuri



Orix Blue Wave



1009



1036





Osaka Kintetsu Buffaloes



1005



943





Seibu Lions



1003



998





The opinions I read indicate that everyone thinks the Tokyo Dome, where the

Giants and Fighters play, is an extreme hitters’ park; it may be that the

Yomiuri score in 2000 was an aberration.

Later this week, we’ll look at the top players in Japan over the last few

seasons.

Clay Davenport is an author of Baseball Prospectus. You can contact him by

clicking here.