elaine > wrote:

> Anyone know what it's called. Not soya or teriaki. It has a lighter and
> somewhat different flavour.

The sauce is called "tentsuyu". According to the fairly canonical
cookbook by Shizuo Tsuji, Koichiro Hata, and Yoshikatsu Saeki, it is
often made with a mixture of the following:

19 fl. oz. dashi
5 tablespoons dark soy sauce
5 tablespoons mirin
1.8 oz. bonito flakes

The sauce is flavoured with:
6 tablespoons daikon, finely grated
2 teaspoons ginger, finely grated

Victor