Democratic Party of Japan kingpin Ichiro Ozawa said Feb. 1 that he has undergone a second round of questioning by prosecutors over accounting irregularities involving his fund management body.

Speaking to reporters at his weekly news conference, Ozawa — the ruling party's secretary general who has been dubbed "the shadow shogun" — said he spent three hours Jan. 31 speaking to prosecutors about his role in the scandal that has led to the arrests of his former aides.

Ozawa said that although it is highly unlikely, if he were to be charged with a crime over the scandal he would have to take "grave responsibility."

"I don't expect to be held criminally responsible since I haven't received any illicit funds," Ozawa said. "But supposing I were (to be charged), I believe I would have to bear grave responsibility."