Katsudon is a very popular Japanese food which most of Japanese people know. But there are several tastes of katsudon throughout Japan. When you order katsudon in Kansai, you are served a bowl dish which is put tonkatsu, pork cutlet, with egg and onion on the rice. It is in the first picture below. When you order katsudon in Fukui prefecture, you will be served with a bowl dish which has tonkatsu with a sauce on it. It is the the second picture below. When you visit Kansai I recommend you to eat both.