A market authorization for radio products in Japan is a  requirement for the marketing of

products within the country.

The exact certification process for a market approval depends on the device itself or the

technologies and interfaces used in the device. If the product incorporates radio technology,

the certification process is required under the Japanese Radio Law.

The Technical Conformity Mark is a proof that the radio equipment conforms to the technical  regulations specified in the Radio Law, and it is affixed on each piece of radio equipment.

The use radio equipment which has no Technical Conformity Mark affixed can be an infringement of the Japanese Radio Law.

Sources:

https://www.tele.soumu.go.jp/e/index.htm

https://www.cetecom.com/en/certification/mic-certification/