7. Is there a ban on anonymous donations to political parties?

Source: 
政治資金規正法, 1948 (2022改正)
Political Funds Control Act, 1948 (as amended by Act No.68 of 2022)

第二十二条の六 何人も、本人の名義以外の名義又は匿名で、政治活動に関する寄附をしてはならない。
2 前項の規定は、街頭又は一般に公開される演説会若しくは集会の会場において政党又は政治資金団体に対してする寄附でその金額が千円以下のものについては、適用しない。

Article 22-6 1 No person shall make a donation related to political activities under any name other than their own or anonymously.
2 The preceding provision shall not apply to donations made to a political party or any political funding organization at a street location or at the venue of a publicly open speech or meeting, where the amount of such donation is one thousand yen or less.

Anonymous contributions are banned, with the exception of donations of 1,000 yen or less made to a political party or any political funding organization at a street location or at the venue of a publicly open speech or meeting.