Itagaki speaks with Joystiq
Itagaki speaks about Ninja Gaiden: Dragon Sword and the choice to bring it to the DS. Apparently, he didn't do it because the DS sells like 24K gold hotcakes or because he believes it to be a superior system to the PSP (hint: he does), but because of his children. Yup, his kids wanted a game on the DS, so he obliged.
The remainder of the interview focuses on his other projects at the moment, which are for other platforms, but we suggest you read it anyway.