If you are interested in getting a better understanding of the HID lamps and ballasts that were used in Japan, I have found this technical document that gives detailed information about them. However, you will need Google Translate to read the document if you can't speak Japanese. You could try using the mobile version as it allows screenshots and photographs of pages to be translated into your native language:

https://www.jlma.or.jp/tisiki/pdf/guide_hid.pdf