- Wipe kombu with a damp cloth
- Add water and kombu to a medium-sized pan. Let the kombu sit in the cold water for 20 minutes
- Bring water and kombu to a boil. Remove kombu just as water starts to boil (either discard or save to use for another recipe or application)
- Toss the bonito flakes into the boiling water, then turn off the heat. Let the flakes sit for 2 minutes (the flakes will sink to the bottom)
- Set a tightly-woven mesh strainer over a mixing bowl. Line the strainer with cheesecloth or a paper towel. Pour the stock through the strainer. Stock keeps for 3-5 days in the refrigerator
Note: The used fish flakes and kombu can be reserved for niban dashi (“number two” dashi; a weaker version)