This has literally never occurred in the six years Microsoft has sold a gaming console in Japan.  Microsoft sold 17,673 Xbox 360 last week in Japan while the PS3 sold 17,434 and the PS2 sold 10,209 consoles.  This amazing success is attributed to the Xbox 360 exclusive Ace Combat 6 and a new 360 Pro bundle with Forza Motorsport 2 and Viva Pinata for about $300. 

Microsoft not only has a great lineup for North American and European gamers but has also got specialized games geared for the Japanese audience coming out this fall.  The exclusive deal with Namco Bandai (publisher of Ace Combat) has really helped Microsoft get a stronger footing in Japan.  The margin of victory might be small but this is a big step forward for Microsoft.

Source:
http://www.n4g.com/industrynews/News-81937.aspx