I EARNED THE BLACK BELT AND BEAT SENSEI AND GOT THE NINJA MASK AND BECAME A NINJA! Here is how to beat sensei. I hope you have time, because you will need it. You need the black belt. There is no way to beat him without it. You must challenge sensei very many times. Even when you lose, sensei will become weaker, when he becomes weak enough so that he makes a mistake, you can beat him now. He is still good when he is weak, so use all the strategy you have. when he needs a water to win, throw out ice, he needs ice, throw fire ect. When you do beat him, he will give you a ninja speech and the ninja mask and tell you that you can go to the ninja’s secret room and show you where the entrance is in the outer Dojo. It is there that you can buy the ninja costume and other things for money. Click the book in the bottom right corner or go to the shop in the area. I hope you all find this useful. And dont complain because this does not work for you, because it worked for me, and it took a long time. Well, not THAT long.