Put rice in a medium pot or your rice cooker. Pour in the water and sake and mix in the salt. Lay the sweet potato slices on top - you don't need to mix it. If using the rice cooker, just turn it on and wait til it's done! For using a pot, see next step.

If using the pot, cover with a lid, and turn the heat on medium. Listen until you can hear the water start to simmer in the pot, then set a timer for 11 minutes and let it cook. Turn off the heat and let it sit without taking off the lid for 20 minutes.

After 20 minutes, it's ready! Lightly mix in the sweet potatoes into the rice with a wet rice spoon or spatula. Sprinkle with black sesame seeds and serve! (or make onigiri :)