Takayama Ramen

In a medium pot, combine Water and Kombu. Heat over medium-low heat until just before boiling, about 10 minutes. Remove the Kombu.

Bring the Water to a boil, then turn off the heat. Add Katsuobushi and let it steep for 5 minutes. Strain the dashi through a fine-mesh sieve, discarding the Katsuobushi.

Return the strained dashi to the pot. Add Koikuchi soy sauce, Mirin, Sake, and Salt. Bring the broth to a gentle simmer over low heat. Taste and adjust seasoning if necessary. Keep warm.