From April 1, 2019, Japan Patent Office has accepted Japanese PCT applications for applications filed with the Japan Patent Office as the main body in charge of international search, as a subject of PCT collaborative search.
This makes it possible to use the PCT collaborative search with a search fee that is less expensive than English language applications. In addition, it is necessary to submit an English translation (non-disclosure) one month after the provisional acceptance of the application.
Japan Patent Office
https://www.jpo.go.jp/system/patent/pct/seido/pct_kyoudouchousa_shikou.html