Enough to fill to the 3 cup line in the rice cooker
Rinse the beans and place them into the rice cooker.
Fill the rice cooker to the highest marked water line (for a 3 rice cup capacity cooker).
Turn the switch on "okayu" (rice porridge) mode. (If you select a different mode, it will boil over.)
You can use this method with other beans, but after they're done cooking, try one bean. If it's not soft enough, put it through the cycle again.
Story Behind this Recipe
Store-bought cooked beans were always too sweet! But whenever I simmered some in a pot, it overflowed. So, I figured out a way to simmer the beans without having to do anything taxing, like soaking the beans beforehand.
Fresh beans will become soft after 1 session of cooking. This time, I ran the "okayu" course twice. If you divide the beans into small portions and wrap them in plastic, you can freeze individual portions. You could also season to taste. Three cups is about 500 g, which is kind of a lot, so be sure to stir them up while cooking.