Editor’s note: Masahiro Tanaka pitched on the night after this story was published and struck out seven in a four-hit shutout to improve to 12-0 with a 1.24 ERA and extend his scoreless innings streak to 40.

The next time Masahiro Tanaka takes the mound for the Tohoku Rakuten Golden Eagles he’ll be trying to win his 12th consecutive decision since opening day.

Tanaka (11-0) actually hasn’t lost a game since Aug. 19 of last season, and given that he pitched July 2, he’ll probably toe the rubber against the Hokkaido Nippon Ham Fighters on Tuesday night at Tokyo Dome.

It’s easy to look at Tanaka’s win-loss record this year — not to mention his 15-0 mark since last dropping a decision — and conclude he’s the best pitcher in Japan at the moment. After all, no one has more wins or fewer (obviously) losses.

It’s not only wins, but how much Tanaka has contributed to those victories that is making the right-hander stand out.

Winning is the most important thing, of course, but wins are hardly the best evaluator of a pitcher’s worth. There are simply too many factors outside a hurler’s control that factor into wins and losses. The Hanshin Tigers’ Jason Standridge, for example, has the best ERA in the Central League (2.31) and a 4-6 record to show for it.

That said, things aren’t wholly out of pitchers’ hands, and Tanaka has more than done his part.

He leads Japan with a 1.35 ERA and is second in both strikeouts (83) and innings pitched (107). His fielding independent pitching average (a measurement of the factors a pitcher controls) meanwhile is a very good 2.44, and the next run he allows will be the first given up in at least 31 innings.

Where Tanaka has really shined this year is in stamping out the fires opposing lineups try to ignite against him.

Tanaka has been at his best under duress. According to data compiled by Nikkan Sports, opponents are 0-for-12 against him with the bases loaded and hitting just .170 with runners in scoring position. Tanaka has helped create his own trouble (opposing batters have a .333 average against him with a runner on first), but has excelled at sending the opposition back to the dugout empty-handed.

The Eagles ace also has a left-on-base percentage (which measures how many runners a pitcher strands) of 86.8, as teams have yet to figure out how to mount a constant offensive against him.

He’s not striking out quite as many hitters as he usually does, but his defense has done the job behind him at critical times.

Tanaka has been dominant for much of the season (only the Seibu Lions’ Yusei Kikuchi has come close to matching him on a sustained level) and is filling the void at the top of the NPB pitching ranks created when Yu Darvish headed to the majors, ironic since Tanaka may eventually follow him to the U.S.

Prior to the season, an at times lackluster showing during the 2013 World Baseball Classic knocked some of the shine off Tanaka, who was 1-0 with a 2.57 ERA in seven innings after entering the tournament billed as “Japan’s Ace.”

‘Ma-Kun’ has regained the crown in recent weeks.

He’s Rakuten manager Senichi Hoshino’s trump card, and down the stretch the Eagles will hope the schedule works out in their favor — that is, in a way that sees Tanaka scheduled to take the hill in the most important games.

His presence should also work to take the pressure off Rakuten’s position players in the field as well as at the plate.

The Eagles can put Tanaka on the mound and almost know they’re going to win, or at least have a good shot at coming out on the right side of the score. Those are the types of things that don’t go unnoticed, and the fiery Tanaka has set a strong example for the younger members of Rakuten’s pitching staff.

The Eagles are a dangerous bunch if Tanaka and the other pitchers keep them in game long enough for Andruw Jones, Casey McGehee and Co. to get loose at the plate, a formula that’s helped vault Rakuten into a two-game lead atop the Pacific League standings.

Eleven straight wins don’t tell the full story of the season Tanaka is having. To this point he’s been so good, focusing on his 11-0 record almost doesn’t quite do him justice.