Clean the konbu with wet towel. Put the konbu and water in a donabe ceramic pot and leave it for a few hours. Cut blocks of tofu into 5 to 8 pieces of yakko (3-4 cm dice size). Put the pot over low heat at the table. Add tofu in the pot and simmer.
Put dashi soup stock, soy sauce, and mirin in a pot and heat to make dipping sauce. Pour the dipping sauce into individual bowls. Add some topping in the bowl and eat boiled tofu, dipping in the sauce.