Makes about 1 ⅓ cups
Adapted from Japanese Farm Food by Nancy S. Hachisu
2 cups (456 gramsl) water, plus more as needed
1 6-inch (15 cm) length of kombu
Place water and kombu in a medium saucepan and set over medium-high heat. Just before the water comes to a boil, remove the kombu and discard. Add the dried bonito shavings and simmer for 8 minutes, then turn off heat and let stand 8 minutes.
Pour the dashi through a fine-mesh strainer set in a 2- or 4-cup measuring cup. You should have 1⅓ cups (304 grams) dashi. If you do not, add water (pouring through the strainer holding the strained katsuobushi) to make the amount of liquid needed. Keep chilled in the fridge, use within a day or so.