Oroshi Soba

To prepare the dashi, gently wipe the Kombu with a damp cloth. Place the Kombu and 600 grams of Water in a pot and let it soak for 30 minutes. Heat the pot over medium-low heat. Just before the Water comes to a boil, remove the Kombu.

Increase the heat to medium-high and bring the Water to a boil. Add the Katsuobushi, reduce heat to low, and simmer for 30 seconds. Turn off the heat and let the Katsuobushi steep for 5 minutes. Strain the dashi through a fine-mesh sieve, discarding the solids.

To make the mentsuyu, combine 200 grams of the prepared dashi with the Usukuchi soy sauce, Mirin, Sake, and Sugar in a small saucepan. Bring the mixture to a gentle simmer over medium heat, stirring until the Sugar is fully dissolved. Remove from heat and let the mentsuyu cool completely.