Prepare the shimeji mushrooms by trimming the roots and separating them. Grate the daikon radish and drain the excess water. Cut the kaiware sprouts in half.

Cut the salmon into bite-sized pieces, season both sides with salt and pepper, and coat with potato starch.

Heat salad oil in a frying pan over medium heat, add the salmon, and fry until golden on both sides. Remove and set aside.

In a pot, combine the sauce ingredients and bring to a boil. Add the grated daikon, salmon, and shimeji mushrooms, and simmer over low heat for 5 minutes.