Put red beans in a pot with 4-5 cups of water. Let boil for 5 minutes and discard water.

In a clean pot, place red beans and 4-5 cups of water, cover, and let it simmer at low heat for 1 1/2 to 2 hours (add more water to keep above the beans). The beans should now be very soft, easily crushed between fingers.

Strain water, but save the water. Put soft beans back in the pot with sugar at medium high heat and constantly stir and mix about 10 minutes until forming a paste that looks shiny but still loose. Put the water back to the pot, add a pinch of salt, and stir. Cook until hot, and keep it warm at low heat.

Bake mochi in a toaster oven until browned and expanded. Put the mochi to a bowl and pour soup over.