1To prepare dashi, wipe the Kombu with a damp cloth, then soak it in 350 grams of Water for 30 minutes. Heat the Kombu and Water gently over medium-low heat. Just before it boils, remove the Kombu. Bring the Water to a boil, then turn off the heat and add the Katsuobushi. Let it steep for 5 minutes, then strain the dashi through a fine-mesh sieve, discarding the Katsuobushi.