Gomoku Udon

In a pot, combine water and kombu. Let it soak for 30 minutes. Heat the pot over medium heat, just before it boils, remove the kombu. Add katsuobushi to the simmering water. Turn off the heat and let it steep for 5 minutes. Strain the dashi stock through a fine-mesh sieve, discarding the katsuobushi.

In a separate pot, combine 800 grams of the prepared dashi stock, usukuchi soy sauce, mirin, sake, and salt. Bring to a gentle simmer over medium-low heat. Keep warm.

Cut chicken thigh into bite-sized pieces. Briefly blanch the chicken thigh in boiling water for 1 minute, then drain.