Chikara Soba

Wipe kombu gently with a damp cloth. Place kombu and 1000g water in a pot. Heat over medium-low heat and remove kombu just before the water boils (around 80-90°C).

Bring the water to a boil, then turn off the heat. Add katsuobushi to the hot water. Let it steep for 30 seconds, then strain the dashi through a fine-mesh sieve lined with cheesecloth. Do not squeeze the katsuobushi. Set aside 800g of the prepared dashi for the tsuyu.

In a clean pot, combine 800g dashi, koikuchi soy sauce, mirin, sake, and salt. Bring the tsuyu to a gentle simmer over medium heat. Do not boil vigorously. Keep warm.