Editing Iteration mark (section)

===Kanji===
[[File:Vertical ideographic iteration mark.svg|thumb|upright=0.3|{{lang|ja|〻}}, an iteration mark (derived from {{lang|ja|𠄠}}) used only in vertical writing.]]

The formal name of the kanji repetition symbol ({{lang|ja|々}}) is {{nihongo||同の字点|dōnojiten}}, literally "same character mark", but it is sometimes called {{nihongo||のま|noma}} because it looks like the katakana {{nihongo||ノ|no}} and {{nihongo||マ|ma}}. This symbol originates from a simplified form of the character {{lang|ja|[[wikt:仝|仝]]}}, a variant of {{nihongo3|"same"|[[wikt:同|同]]}} written in the [[Cursive script (East Asia)|grass script]] style.<ref>{{cite web |url=http://kanjibunka.com/kanji-faq/old-faq/q0009/ |script-title=ja:漢字文化資料館 漢字Q&A〈旧版〉 Q0009 「々」はなんと読むのですか？ |language=ja}}</ref>

Although Japanese kanji iteration marks are borrowed from [[#Chinese|Chinese]], the grammatical function of duplication differs, as do the conventions on the use of these characters.

While Japanese does not have a grammatical [[plural]] form ''per se'', some kanji can be [[reduplication|reduplicated]] to indicate plurality (as a collective noun, not many individuals). This differs from Chinese, which normally repeats characters only for the purposes of adding emphasis, although there are some exceptions (e.g., {{lang|zh|人}}, {{Transliteration|zh|rén}}, "person"; {{lang|zh|人人}}, {{Transliteration|zh|rénrén}}, "everybody").
* {{nihongo3|person|人|hito}}; {{nihongo3|people (not "persons")|人々|hitobito}}
* {{nihongo3|mountain|山|yama}}; {{nihongo3|many mountains|山々|yamayama}}

However, for some words duplication may alter the meaning:
* {{nihongo3|piece, object|個|ko}}; {{nihongo3|piece by piece; individually|個々|koko}}
* {{nihongo3|time|時|toki}}; {{nihongo3|sometimes|時々|tokidoki}}
* {{nihongo3|next day|翌日|yokujitsu}}; {{nihongo3|lit. "next next day" (two days later)|翌々日|yokuyokujitsu}}

Using {{lang|ja|々}} instead of repeating kanji is usually the preferred form, with two restrictions:
* the reading must be the same, possibly with sound change (as above), and
* the repetition must be within a single word.

When the reading is different, the second kanji is often simply written out to avoid confusion. Examples of such include:
* {{nihongo||日日 日にち|hinichi}}
* {{nihongo||湯湯婆 湯たんぽ|yutanpo}}
* {{nihongo||出出し 出だし|dedashi}}

The repetition mark is not used in every case where two identical characters appear side by side, but only where the repetition itself is etymologically significant—when the repetition is part of a single word. Where a character ends up appearing twice as part of a compound, it is usually written out in full:

* {{nihongo3|"democracy"|民主主義|minshu-shugi}}, from {{lang|ja|民主}} + {{lang|ja|主義}} ("democracy" + "principle"); the abbreviated {{lang|ja|民主々義}} is only occasionally seen. One notable exception is in signs for {{Nihongo|neighborhood associations|町内会|chōnaikai}} – the name of neighborhoods often end in {{Nihongo|"... neighborhood"|〜町|-chō}}, which is then suffixed with {{lang|ja|〜町内会}} yielding {{Nihongo|"... neighborhood neighborhood association"|〜町町内会|-chō-chōnaikai}}, which is then informally abbreviated to {{lang|ja|〜町々内会}}, despite the word break.

Similarly, in certain Chinese borrowings, it is generally preferred to write out both characters, as in {{lang|ja|九九}} ({{Transliteration|ja|ku-ku}} [[Chinese multiplication table]]) or {{lang|ja|担担麺}} ({{Transliteration|ja|tan-tan-men}} [[dan dan noodles]]), though in practice {{lang|ja|々}} is often used.

In [[tategaki|vertical writing]], the character {{lang|ja|〻}} ([[Unicode]] U+303B), a cursive derivative of {{lang|ja|𠄠}} ("two", as in [[#Chinese|Chinese]], above), can be employed instead, although this is increasingly rare.