Place aduki bean in large bowl and cover with water by 4 inches. The beans will swell overnight so use plenty of water. When it is time to make the stew, drain the beans and place in a medium saucepan. Cover with water and bring to a simmer over medium high heat. Let simmer for 40 minutes.
Meanwhile pour 1 cup boiling water into a heat proof container and add the dried porcini mushrooms. Stir to submerge the mushrooms and set aside for 30 minutes. Drain the mushrooms and strain the water through a coffee filter. Set mushrooms and mushroom water aside.