We refer “sauce” (pronounced So-su ソース) as a thicker version of Worcestershire sauce. So-su comes in three types: thin, medium-thick, and extra thick.
Thin sauce is called Usutah So-su (ウスターソース) and this is similar to Worcestershire sauce. The medium-thick sauce is called Chuno So-su (中濃ソース). Finally, the thick sauce is Tonkatsu So-su (とんかつソース) which is used for Tonkatsu or other deep fried dish. The major sauce brand in Japan is called Bulldog (see the picture above).
For Tonkatsu Sauce and Okonomi Sauce recipe, click here.
For Yakisoba Sauce recipe, click here.
For Takoyaki Sauce recipe, click here.