Masahiro Tanaka, Wlad Balentien, and Japan’s “Juiced” Ball

In Commentary And Analysis by GW28 Comments

In 2013, former Mariner Wladimir Balentien broke Sadaharu Oh’s 49-year old single-season homerun record in Japan, hitting 60 homers over the course of a 144-game schedule.  The story trickled out to US news services with an asterisk firmly attached. The narrative went something like this: yes, he broke the record, but only because the ball was juiced. In fact, once it was uncovered, those nationalists in NPB were so upset that they demanded the resignation of commissioner Ryozo Kato. While never spelled out in anything like those terms, stories tended to lead the reader right up to the brink of those conclusions. I, at least, accepted that narrative*; it seemed consistent with previous efforts by Japanese players to prevent a foreigner from breaking Oh’s cherished record. In this case, however, the narrative was false- uniquely false, perhaps- but false.  All of the facts in the story were accurate, but simply mashed together inappropriately to create a false impression of cause and effect.

*Until Yakyu Night Owl raised forceful objections on twitter.

Juiced or Raised from the Dead?

I took a look at offensive stats in Japan. Here are R/G levels for Japan’s Central (in which Balentien’s Yakult Swallows play) and Pacific Leagues.


It turns out that the ball was “juiced” in 2013, but only relative to 2011 and 2012 levels. In those two seasons, runs were historically scarce in Japan. 2013 levels were up, but slightly lower than pre-2011 levels. Homerun rates tell a similar story. (I’ve included 1964 numbers in the table for reference, as that’s the year that Oh set the original record).

Pacific Central Pacific Central
2005-2010 4.2 4.1 0.031 0.035
2011-2012 3.4 3.1 0.019 0.021
2013 4.0 4.0 0.026 0.031
1964 3.8 3.6 0.027 0.030

The more accurate version of the narrative (which seems to be common knowledge to everyone involved with Japanese baseball) is as follows: In 2011, a standardized ball was introduced into the league. Prior to that season, each team ordered their own. Offense declined sharply with the new ball, and prior to the 2013 season, someone at NPB (allegedly secretary general Kunio Shimoda) ordered a livelier version and covered it up. Early-on in 2013, just about everyone realized the ball was different, and the players complained that they should have been informed for the sake of contract negotiations. For his part, Kato denied that the ball had changed right up until an investigation proved that it had, after which he received enormous pressure to resign. He finally conceded later in the season, and that news just happened to be reported right alongside news of the Balentien homerun record.

Tanaka and the Dead Ball Era

Two of Masahiro Tanaka’s best three seasons coincided with the Japan’s dead-ball era. In 2011, he threw 226 innings with an ERA of 1.27, then 185 innings and 1.87 in 2012. levels. How much of a boost did Tanaka get from the reduced offense over those two seasons?

NBP Tanaka NPB Tanaka*
2007-2010 3.84 3.04 0.032 0.024
2011-2012 2.97 1.53 0.020 0.011
2013 3.64 1.27 0.028 0.010
*These are estimates, as I don’t have Tanaka’s complete stat line. They should be pretty accurate.

Well, that’s difficult to say.  Tanaka’s numbers improved sharply in 2011 and 2012, but he was equally dominant in 2013, throwing 212 innings with a 1.27 ERA.  While the league moved back towards previous levels, Tanaka pitched as if he alone was still using the dead ball. His homerun rate was virtually unchanged.

What about the rest of his peripherals? I hypothesized that a sudden change to a dead ball would boost strikeout rates for power pitchers, as they could tread the upper reaches of the strike zone for swings and misses with less fear of getting taken deep.

K% BB%
Pacific  Central  Tanaka Pacific Central Tanaka
2007-2010 17.9 17.7 21.9 7.5 7.4 6.7
2011-2012 17.1 17.9 26.2 6.7 7.4 2.9
2013 17.4 17.7 22.3 8.3 8.5 3.9

It turns out that league-wide, that wasn’t the case. The strikeout rate barely moved. Tanaka, on the other hand, did get significantly better at striking people out. Whether that can be attributed to him leveraging the new ball to his benefit is a question for Japanese Harry Pavlidis. It’s possible that those two seasons simply happened to coincide with the peak of Tanaka’s powers. Regardless, I do think it’s notable when comparing him to previous Japanese imports.

What we can say with relative confidence is that over the course of his career, Tanaka has gotten better at controlling the strike zone and keeping the ball in the park. In and of itself, that’s a desirable trait for someone who just signed a long-term deal to pitch in Yankee Stadium.

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  1. rattier

    Thanks for setting that straight. So Tanaka really had one crazy good year instead of three. This just reinforces the creeping feeling I had that Tanaka was going to massively underperform if the Cubs signed him for big money. Of course, now that they didn’t, I’m sure he’ll be Yu Darvish levels of awesome.

    I still think its alright he wasn’t signed, with the added bonus of the front office showing that they were willing to spend big (but not crazy) for a guy they wanted. One of these days they’ll have to actually get the damn guy though.

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  2. dmick89, Sweatpants Guru

    @ GW:
    Probably, but I’d have to take a closer look, which I’ll try to do tomorrow. I’ll send you an email.

    Good writeup here, GW. Considering the cover-up, I wouldn’t be too terribly surprised to learn that Tanaka was given a different ball. I think it’s unlikely and probably would have come out by now, but I do think it’s possible.

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  3. dmick89, Sweatpants Guru

    They’re centered. Take a look at what I did. It’s pretty simple, but the method you were using has been overruled in the css file on purpose. I don’t remember what purpose that was (probably to fix some other coding error I made), but it did have a specific purpose at one time. (dying laughing)

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  4. BVS, not sure if coming or going

    @ rattier:

    Great article GW.

    Rattier, I’m not sure the conclusion is that sharp, considering that Tanaka’s 2013 was closer to 11-12 than previous. K% went back to pre-2011 levels, but BB% did not, particularly as differential from league (league BB% increased ~1% from 11-12 to 13, and so did Tanaka’s). Could be benefit from the dead ball, could be he “went to the next level” in maximizing his skills. Probably some of both.

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  5. Author

    @ dmick89, Sweatpants Guru:

    I don’t really think he was using a different ball. Just that if all you had were his stats, you would think that it stayed dead in 2013.

    @ rattier:

    @ BVS, not sure if coming or going:

    I think it’s hard to say how good he was in ’11-12. Clearly, his results are less impressive given league-wide offensive levels. On the other hand, there’s a limit on how good someone can be. As offensive production dropped, it’s possible that the separation between elite and great was masked, so to speak.

    I do think it would be interesting to see if there was a change in how he approached hitters, based on pitch f/x or the equivalent. And how that carried over into 2013.

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  6. Rice Cube

    Did you guys try comparing Yu’s pre-MLB stats (when the ball was still live) to Tanaka’s “dead ball” stats? Yu would have several data points at the juiced levels and one (2011) that would be “dead” if I’m not mistaken.

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  7. Akabari

    @ Edwin:
    “Cubs sign Jason Hammel. Maybe Theo and Jed confused him for Cole Hammels. We’re still a garbage team”
    There you go guys I wrote the article. Don’t worry about it.

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