Tonkatsu sauce
Tonkatsu sauce is a thick sauce served with tonkatsu, the Japanese pork cutlet. It is a thick Japanese Worcestershire-type sauce. As with most Japanese Worcestershire sauces, it is vegetarian and similar to a brown sauce, with tomatoes, prunes, dates, apples, lemon juice, carrots, onions, and celery among its ingredients.
The first Tonkatsu sauce was made in 1948 by Oliver Sauce Co., Ltd. of Hyogo Prefecture. While generally similar to a traditional brown sauce, it is vegetarian. The Bull-Dog brand of tonkatsu sauce, for example, is made from malt vinegar, yeast, and vegetable and fruit purees, pastes, and extracts.