Many reasons... First of all they should not have involved the United States of America, even Hitler knew that to win a war, you don't involve the Americans, you can even find quotes of Hitler talking about that. Even the Admiral in charge of the attack on Pearl Harbor knew it was a horrible idea "I can run wild for six months … after that, I have no expectation of success".
Other than involving the Americans, the Japanese should've attack up into the USSR (Russia) opening up a new front and forcing the Russians to move man power to their east.
Another is that Japan often ignored their German allies when they advised against certain campaigns and attacks, which were strategically horrid ideas.
