There are not many restaurants offering Muslim cuisine in Japan, but their number is gradually increasing, mainly in Tokyo and Osaka.
There are places serving food said to be halal, but in general it is not well known.
However, at Touch-Japan we indicate that our fish, vegetables, and fruits are natural, and label meat as halal certified.
Recently Japanese food manufacturers have begun selling halal seasonings (such as non-alcoholic soy sauce, etc.) for Muslim cuisine, and it seems that Japan is becoming increasingly Muslim-friendly.