11. Prepare dashi stock: Combine 300 grams of Water and 5 grams of Kombu in a saucepan and let it soak for 30 minutes. Heat over medium-low heat until just before boiling, then remove the Kombu. Add 10 grams of Katsuobushi, bring to a boil, then immediately turn off the heat. Let the Katsuobushi steep for 5 minutes, then strain through a fine-mesh sieve, reserving 200 grams of the Dashi stock.