How do I get channel IDs for all YouTube channels in Japan?

I want to get channel IDs for all YouTube channels in Japan.

I tried to set the following parameters and call /search of YouTube Data API v3.

part: idmaxResults: 50regionCode: jptype: channel

pageInfo.totalResults in the API response is about 200,000 but actually I can only get 583 channel IDs.583 is too little even if pageInfo.totalResults is an approximate value.

I would like to know how to get all the channel IDs in Japan, either by using the API or not.

I hope you will be able to provide the related information.