First soup stock
4″ square dried kelp (kombu)
1 3/4 pints water
1/2 oz dried bonito flakes (hana-katsp uo)
How to prepare
Wipe kelp with damp cloth and cut a 1/2″ fringe along one side. Put kelp in cold water, heat moderately until just under a boil. Pull out kelp and reserve. Bring water to boil, add bonito. Remove from heat and let stand for 2-3 minutes. Strain through a sieve until clear; reserve damp fish flakes.
Second soup stock
Take kelp and bonito leftover from first stock making and combine with 1 1/4 pints water and simmer over moderate heat for 4 minutes. Strain and discard solids.