The Kombu and the Katsuobushi may be taken from the Ichiban Dashi recipie. Put the cooked Kombu anf Katsuobushi with 2 Pt cold water in a medium sized saucepan and bring to boil. Add all Katsuobushi, reduce heat and simmer for 5 minutes. Strain out Kombu and Katsuobushi, discard Kombu and Katsuobushi. Can be kept at room temp for 8 hrs or refrigerated for 2 days.

From "Recipes-The Cooking of Japan" from Time-Life International, c1965.