The Japanese prosecutors are conservative in charging which in turn leads to a near 0% acquittal rate.

「有罪率99％」という誤解 2020年01月02日

警察が逮捕して送検した被疑者を検察が起訴する率は63％で、有罪件数を逮捕件数で割ると国際的な平均に近い（ジョンソン『アメリカ人のみた日本の検察制度』）。多くの国では容疑者を起訴することは検察官の義務とされているが、日本では起訴するかどうかは検察官の裁量にゆだねられているため、確実に有罪になる者しか起訴しないからだ。

これは英語の引用がほしかったな。

The Japanese Way of Justice: An Up-close Look at Japan’s Jack McCoy A Review of The Japanese Way of Justice: Prosecuting Crime in Japan By David T. Johnson Kent Anderson

Johnson shows how prosecutors’ culture is responsible for one of the chief differences with the United States, that Japanese prosecutors would rather err on the side of not charging a questionable suspect (i.e., “suspending prosecution”), while United States prosecutors inevitably err in favor of charging.44 This is one of the core discoveries of this book. It turns, in part, on the fact that Japanese prosecutors focus on rehabilitation along with a belief—or fear—that a person once charged will be irrevocably tainted.45 In contrast, the U.S. prosecutorial culture, particularly with its political  nature, makes it in a prosecutor’s interest to risk convicting an innocent person rather than risk letting a guilty one go.46

45 This fear of tainting suspects in the public’s mind circularly relates back to Japan’s near 0% acquittal rate, discussed below. That is, because Japanese courts find guilty essentially everyone charged with a crime — politicians excepted of course—the public’s assumption that a charged suspect is guilty seems quite reasonable. Thus, to avoid this taint, the prosecutors are conservative in charging which in turn leads to a near 0% acquittal rate. JOHNSON, supra note 4, at 215, 220-230.