「PREP」Put the shiitake in a bowl of water to soak for at least an hour. (If you don’t have the time, put shiitake in a bowl with a bit of sugar, cover and microwave for 2 minutes.) If making it yourself, prepare the mentsuyu sauce. Prepare the kinshi tamago. Chop the scallions. Slice the myoga. Grate the ginger. Julienne the shiso. Sprinkle the chicken with a pinch of salt and 2 tablespoons of sake. Cover and microwave for 3-4 minutes, or until cooked.
Put the sake, mirin, soy sauce, sugar, shiitake and 100 mL of the shiitake soaking liquid in a pot. Cook over low heat with a drop lid for 15 minutes. Slice the shiitake.
Bring a large pot of water to the boil and add the somen, cooking according to package instructions (usually 1-3 minutes). Drain and thoroughly rinse the somen under cold running water, rubbing with your hands to remove excess starch (but let it cool down under the water a little first!)
Arrange the somen in coils on a plate (or place into one large shared, or four individual, bowls of ice water. Or drop a little at a time down a bamboo slide for your guests to catch with their chopsticks!) Serve with the dipping sauce and toppings.