Put rice in a bowl. Wash and pour water out, then repeat 2 more times. Place rice and water in a heavy pot. Let it soak for 30 minutes.

Immediately before cooking, add salt and sake and stir. Add Kabocha and bring it to a boil on high heat without lid. When it reaches the rapid boil, put the lid on and reduce heat to simmer for 15 minutes.

Let it stand for 10 minutes (don't open the lid.) Fluff the rice with spatula (kabocha will be so soft that it will be mashed a little bit, but that's OK.)