〻

• 々 (in horizontal writing)

〻

1. (in vertical writing, informal) An iteration mark denoting the repetition of the previous hanzi.

二 (usually appearing as 〻) is used in casual writing to represent a doubled character in vertical writing, but is never used in formal writing or printed matter.

 

Japanese Wikipedia has an article on:

踊り字

Wikipedia ^ja

• 々 (in horizontal writing)

• Name: 二(に)の字点(じてん) (ni-no-ji-ten, “二 (“two”)-mark”)

〻 

1. (in vertical writing, now rare) An iteration mark denoting the repetition of the previous kanji; the repeated character does not necessarily have the same pronunciation as the first due to rendaku.

• 漢字文化資料館 漢字 Q&A コーナー Q0009 「々」はなんと読むのですか？