For the udon
4 oz (125 g) dried udon noodles
For the meatballs
½ lb. (500 g) ground chicken
1 tsp. salt
¾ tsp. shichimi togarashi or ¼ tsp. ground red pepper (I used Korean pepper), or to taste
For the soup
8 cups (2 liters) water
1 cup (100 g) shaved burdock (about 1 whole) (optional; I did not use it)
1 cup (60 g) sliced fresh mushrooms, preferably eringi or shiitake
one 3 x 5-in (7.5 x 12.75-cm) sheet fried tofu (abura-age), rolled in paper towel to remove excess oil, thinly sliced
½ cup (40 g) thinly sliced leek
¼ cup soy sauce
Bring a pot of water to a boil. Cook the udon according to packaged instructions (about 8 to 10 minutes, or until they are slightly underdone). Drain, rinse, and drain again. Set aside.
To make the meatballs, combine the ingredients in a small bowl. With damp hands, form 1 teaspoon of the mixture into a ball. Repeat with remaining mixture; you should have about 18 meatballs.
To make the soup, bring the water to a boil in the same pot used to boil the udon. Add the burdock, if using, and the mushrooms and fried tofu. Reduce the heat to medium and simmer 5 minutes. Add the meatballs, cover, reduce the heat to low and cook 5 minutes more, or until the meatballs are cooked through. Add the leek, soy sauce and cooked udon. Cook 1 minute more to heat through.