"Scholars say the biggest reason for Japan's very high conviction rate is the country's low prosecution rate and the way Japan calculates its conviction rate is different from other countries.[2][3][4] According to them, Japanese prosecutors will prosecute only the very few cases in which they are most likely to be guilty and not many others."

https://web.archive.org/web/20220712033655/https://www.nippo...

I don't think it's reasonable to assume anything happens if there's an alternative explanation.