Enter Kamui and go to the right of the Guardian Sapling to find the Kokari boy and his dog Ume. To the right of them is the third dojo with a big pile of snow close to it. If you power slash it enough times, an ice statue of Issun x1000 will appear. Destroy it with Inferno and go in the dojo, then go back out. The pile of snow reappear. If you power slash it again, a statue of Sakuya will appear. Repeat the process for a new statue every time.