Bank of Japan Gov. Haruhiko Kuroda has a new strategy to support his country's listing economy: talking up China's.

It's a marked break with what other Japanese officials are saying. Finance Minister Taro Aso and economy czar Akira Amari have been eager to blame China's slowdown for Japan's woes. It's somewhat surreal to see them urge Beijing to implement economic reforms when they've done nothing of the sort in Tokyo — and with more time on the job than their Chinese counterparts.

Kuroda, however, is guilty of taking things to the opposite extreme. Speaking in New York, he challenged the negativity shrouding Asia's biggest economy, saying he's "reasonably sure" China will grow between 6 percent and 7 percent this year and next — a prediction that hardly anyone else has endorsed. Kuroda has effectively lashed his credibility, and his legacy, to China's trajectory. It's not hard to understand why he might have felt he had no choice.