- 2 quarts water
- Five 6-inch squares kombu (kelp)
- 1 cup tightly packed katsuobushi (bonito fish flakes)
- Wipe the kombu with a damp cotton cloth or paper towel. In a large pot, bring the water and kombu almost to a boil over medium heat. This should take about 10 minutes. Immediately before the water reaches a boil, remove the kombu, and either discard it or save it for preparing “second fish stock.” Use the liquid (kombu dashi) as a vegetarian stock, or follow the remaining instructions to make ichiban dashi (“first fish stock”).
- Immediately after removing the kelp, add the katsuobushi (bonito flakes) all at once. Wait 10 seconds or until the liquid comes to a boil. Then turn off the heat, skim off any foam, and let the mixture stand for 2 minutes.
- Strain the stock through a sieve lined with a tightly woven cotton cloth. Discard the bonito flakes, or save them with the kombu to make second fish stock.
- Refrigerate the stock, tightly covered, for up to four days, or freeze it into cubes in an ice tray.