When asked about the joint air-sea battle initiative by former defense minister Koike at the Budget Committee of the House of Representatives on Feb. 1, he said it was not understandable, amazing the auditorium.

The U.S. is now pushing forward the air force-navy joint battle initiative to cope with Chinese army's modernization drive.

He was also derided for his lack of elementary knowledge about "security" unbecoming for the defense chief.

The Japan Defense Ministry laid down the concept of mobile defense capabilities emphasizing the mobility of "Self-defense forces" in the 2010 defense guidelines in line with the U.S. "joint battle initiative".

Tanaka was derided the following day also for revealing his low intelligence. When asked how Io Island housing a SDF base is pronounced, he stammered he thinks it is Ioto, stunning the people.

Commenting on this, Japanese newspapers jeered at him, saying "Defense Minister Tanaka discloses his poor knowledge again" and "the defense minister reveals his novice."