Japanese Sauce - Soba Tsuyu And Soba Zuyu - cooking recipe

Ingredients

1 cup dashi
3 tablespoons shoyu
2 tablespoons mirin (Japanese Sweet Cooking Wine)
2 tablespoons dried fish flakes (Katsuobushi)
1/3 cup rice vinegar (Su, for Soba Zuyu only)
1 tablespoon tangerine zest, skin shaved (for Soba Zuyu only)
red pepper flakes (optional)

Preparation

Mix the dashi, shoyu, and mirin in a saucepan, and heat to boiling.
Add the katsuobushi flakes, and continue boiling for 1 minute
Strain the mixture through a cheese cloth or a coffee filter, and allow to cool.
Add the rice vinegar (Su) and finely grated tangerine skin (if making Soba Zuyu).
The sauce may be sprinkled with red pepper flakes when served.