To my understanding, there are standardised kanji that have either:

  • No reliable information on how they are to be pronounced OR
  • No reliable information on what they mean OR
  • All of the above.

Do these kanji exist, and if so: What are the current hypotheses on what they mean/how they are pronounced?

2 Answers 2


We call them:

  • No reliable information on how they are to be pronounced → 音【おん】(未詳【みしょう】/不明【ふめい】)字【じ】
  • No reliable information on what they mean → 義【ぎ】(未詳/不明)字
  • All of the above → 音義(未詳/不明)字

幽霊文字 in @naruto's answer is usually considered as a subset of them (technically, meaning/pronunciation of some 幽霊文字 are easily inferrable so they're not true subset).

Some Chinese Characters have unknown meaning/pronunciation even they have reliable source, because it's clearly written in dictionaries that "音未詳"/"義未詳"/"音義未詳". When those massive dictionaries were compiled, they tried to collect characters from all available documents. Some characters only have too sporadic (or single) specimens to reasonably guess what they are. Some others are from previous dictionary with whose description about meaning/pronunciation are lost or unrecorded. The Unicode standard contains a numerous number of those characters because it has unconditionally incorporated all entries in the authoritative dictionaries.

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While they have possibility to be identified through investigation, there was no research encompassing the entire encoded characters as far as I know, thus many of them are just left to be determined.





JIS基本漢字 (aka JIS第1・第2水準漢字) is a set of Japanese characters (including approx. 6350 kanji) established in 1978. It has been widely supported by personal computers since then, but this standard contains several kanji which have no reliable origin.

For example, is a kanji which probably did not exist before the JIS基本漢字 set was established. No one knows its meaning. It has the reading (カ/セイ), but it's a fabricated one for convenience sake.

戸籍統一文字 contains over 50,000 "kanji", many of which are not listed in any dictionary. They have character codes and actually in use in government offices, but I don't know whether you can call them "standardized".

And you can find tons of insane kanji which are not standardized here: 漢字部屋

  • 幽霊文字って、「 ghostly letters」と言ったら間違いはありませんよね? Commented Jun 12, 2016 at 0:28
  • はい、直訳すればそうなりますね。
    – naruto
    Commented Jun 12, 2016 at 1:40
  • How could 彁 appear without any meaning or reading? Did someone just sneakingly add it to the list to confuse people or what?
    – kuchitsu
    Commented Jun 12, 2016 at 10:14
  • 1
    @WillihamTotland「ghost letters」の方は私の耳に自然に聞こえる。「ghostly」だと、白くて揺れてるとかのようなイメージがする。
    – Sjiveru
    Commented Jun 13, 2016 at 2:59

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