1Prepare the dashi stock: Wipe the Kombu with a damp cloth. Place the Kombu and Water in a pot and heat over medium-low heat. Just before the Water boils, remove the Kombu. Bring the Water to a boil, then turn off the heat and add the Katsuobushi. Let it steep for 30 seconds, then strain the Dashi stock through a fine-mesh sieve, discarding the Katsuobushi.