Prepare chestnuts by using kitchen scissors to remove the outer hard skin. Leave the astringent skin intact.
Place them in a saucepan or pot and pour enough water to cover the chestnuts.
Start to heat the pot over high heat to bring it to boil.
Once it has boiled, turn the heat down to low / medium and simmer to cook the chestnuts for about 20 minutes.
Drain the hot water and add cold water so that you can handle the chestnuts but the chestnuts will not get dry.
Carefully remove the astringent skin with hands and set aside all.
Wash the rice and glutinous wheat until the washing water becomes clearer (about 3-4 times). Drain the water completely.
Place the washed rice and the glutinous wheat into a rice cooker.
Pour 2 cups of water and add salt and sake.
Place the chestnuts over the rice.
Close the rice cooker lid and set the rice cooker, following the rice cooker instructions.
When it is cooked, stir gently. Try not to break the chestnuts shape.
Serve in a rice bowl and sprinkle black sesame seeds.
I used glutinous wheat, it can be replaced with sweet rice. If you are not able to access either of these, then cook with rice only. The reason I add glutinous wheat is for its mochi like texture. Cooking time will differ depending on rice cooker.