Dashi for Sesame Dipping Sauce

Place 8 cups of water in a large pot. Add kombu and let steep for 30 minutes.

Place pot over medium heat and bring to a boil; remove kombu and discard. Add 2 tablespoons water and bonito; stir until well combined. When liquid returns to a boil, immediately reduce heat to low; let simmer for 5 minutes, skimming surface as necessary.

Remove pot from heat and let steep 15 minutes. Strain through a fine mesh sieve or cheesecloth; do not press down on or squeeze bonito flakes. Discard solids.