Traditionally Japan's official policy has always been to deny wrongdoing of any kind, and to assert that Japan was the victim, being attacked for no apparent reason. Several historians and teachers have tried to change this over the years, with varying success, but sooner or later the government textbook policy seems to come back to that theme.
http://en.wikipedia.org/wiki/Japanes..._controversies
http://spice.stanford.edu/docs/134
An article from 1988:
http://www.nytimes.com/1988/04/27/wo...-attacked.html
The Wiki and Stanford articles indicate that things have gotten better since 1988, but that in the 21st century it's happening all over again.