Step 1

Place optional kombu in saucepan with water.

Step 2

Heat but do not let water boil.

Step 3

As bubbles appear in hot water, but just before it simmers, remove optional kombu, setting it aside.

Step 4

Add bonito flakes. Keep heat on under pot and allow water to come to boil. Then turn off heat immediately.

Step 5

Bonito flakes will absorb water and slowly sink. Allow 3-5 minutes for this process.

Step 6

Strain broth, reserving bonito. This is First Dashi.

Step 7

For a second, stronger broth put 2 quarts more water back into pot with reserved kombu and bonito.

Step 8

Heat water to barely a simmer (do not boil) for 10 minutes. Strain. This is Second Dashi.