Ingredients

3 strips (about 6 inches each) kombu, wiped with a dry cloth 

2 cups bonito flakes 

1 cup dashi 

3/4 cup soy sauce 

1/4 cup plus 2 teaspoons mirin 

4 1/2 tablespoons lemon juice 

1 1/2 teaspoons grated peeled fresh ginger 

1 1/2 teaspoons grated daikon 

Preparation

Make dashi: Combine kombu and 6 cups cold water in a medium saucepan and bring to just under a boil; remove from heat. Using tongs, remove kombu; discard. Sprinkle bonito flakes into the pan and let steep until they sink to the bottom, about 3 minutes. Strain liquid through a fine sieve. Dashi can be kept in an airtight container in the refrigerator up to 4 days.

Make dipping sauce: mix together dashi, soy sauce, mirin, lemon juice, ginger, and daikon in a bowl to combine.