This is great – thank you so much for compiling and posting!
I had been led to believe by some article which I can’t specifically recall that Darvish’s 2011 performance was not “that good” in the league context, and that in fact he had not led the league in any important categories. I see now that this was completely false, and in fact he led starting pitchers in SO, FIP (to the extent the FIP components translate meaningfully to NPB), K/9 and K% (probably – not quite enough information to do a full calculation). And to the extent he didn’t lead in certain categories (W, CG, SO, ERA, K/BB) he was second to or tied with Tanaka, who clearly stood with Darvish in a cluster apart from the rest of the league.
Assuming the overall NPB talent level is somewhere between AA+ and AAA+, and considering his age, I’m now a lot more comfortable with his MLB prospects. I’m thinking Ubaldo Jimenez might be a good comp for his potential.
Yeah, the popular opinion seems that the NPB is slightly better than Triple-A ball on talent. There are a few factors though that could provide differences in the numbers. For hitters, most turfs are artificial, so groundballs are more likely to go for hits (I think they still have some field with all dirt infields). Second, teams are more risk averse, so they tend to be conservative with their defenses and strategies (a lot of bunting, not a lot of diving, or stretching out hits, etc.), also a lot of the fences tend to be short, according to reports (though apparently this hasn’t resulted in much power spikes, since most of the HR leaders in Japan are usually American players). There are no PETCO parks in Japan.
In terms of helping pitchers, I know the ball was changed to be “less-carrying.” Also, umpiring is notoriously questionable (and if you have seen the movie Mr. Baseball, there has been reports of bias against foreign players in terms of umpiring), and fewer errors are called.
I know these differences don’t make a huge change to the “slightly better than Triple-A” label, but I think they can give a little more context into the NPB numbers overall.