Tosa is a small town on the outskirts of Kochi, Shikoku and has the reputation for the best Bonito catch in Japan. This sauce is from Tosa and used either on its own as a base for other flavours.
Ingredients
2 Tbsp Sake
2½ Tbsp Mirin
2 square Konbu
200ml Soy
2½ Tamari
10g Bonito flakes

Method

Mix sake and mirin over gentle heat until the alcohol is burned off. Add the konbu after wiping it with a damp cloth plus the rest of the ingredients and leave for 24 hours. Stain through a piece of cotton to remove the bonito flakes and konbu. Store in a dark cool place until required. The longer the sauce is aged the better – the sauce in ideal conditions should be used after 4 – 6 months and will keep for up to 2 years.

Sesame Soy Sauce
Add 2 tbsp of toasted white sesame seeds that have been ground to a flaky paste in a Suribachi - Japanese Mortar – to 100ml of the Tosa Soy Sauce.

Plum Soy Sauce
Puree 2 Tbsp of pickled plum flesh – bainiku - or deseed whole red pickled plums and use the flesh - through a fine sieve. Add the puree to 100ml Tosa Sauce Sauce and blend well.

Ginger Soy Sauce
Mix 1 Tbsp of finely grated ginger to 100ml Tosa Soy Sauce.

Horseradish Soy Sauce
Mix 1 Tbsp of finely grated wasabi horseradish to 100ml Tosa Soy Sauce
You can experiment with your own flavourings such as lemon, black sesame , mustard etc.

©Japanese Knife Company 2001. This recipe cannot be reproduced in any form without the express permission of Japanese Knife Company