What Japanese verbs are irregular?

It is quite often claimed that Japanese has only two irregular verbs. However, there are more than ten verbs in modern Japanese which conjugate irregularly.

Suru and kuru

Both suru (to do) and kuru (to come) are highly irregular verbs. None of their conjugations follow the standard patterns.

Conjugation of suru and kuru
Plain suru kuru
Negative shinai konai
Past shita kita
Imperative shiro
seyo (formal)
te form shite kite

See a textbook or reference book for full details.

In Japanese grammar, suru is called a sahen (サ変) verb, and kuru is called a kahen (カ変) verb. There are no other sahen or kahen verbs.

Iku (行く)

Iku (to go) has irregular te form and past tense itte, and itta; if iku was regular, the te form and past tense would be iite and iita respectively.

Honorific verbs

The honorific verbs irassharu, ossharu, kudasaru, gozaru, nasaru (see What is Japanese respect language?) all have an irregular stem, where the ru ending conjugates as i rather than ri. For example, the gozaimasu of arigatō gozaimasu, "thank you". If this conjugated as a regular verb it would conjugate as gozarimasu.

Kureru (くれる)

Kureru has an irregular imperative form kure. If it was regular, the imperative would be kureyo or kurero.

Aru (ある)

Aru, "to have", "to be", is mostly regular, but for its negative nai is used, rather than aranai.

Iu (言う)

Iu is irregular in its pronunciation, varying between yuu and iu.

Some suru verbs such as aisuru

Some suru verbs (see What is a verb?), verbs made by adding suru to a noun, conjugate as if they were two verbs. For example, aisuru "to love" (see How can I say "I love you" in Japanese?) may conjugate as aisuru and aisu, depending on the form. aisu is used for the potential form aiseru "can love", instead of aidekiru. Similarly for verbs such as yakusu (translate).

Tou (問う)

Tou (問う) has an irregular te-form toute (問うて) and past tense touta (問うた).[1][2]


  1. 「問うている」と「問っている」では、どちらが正しいのでしょうか。 (in Japanese)
  2. Discussion at the sci.lang.japan newsgroup (in English)

If you have questions, corrections, or comments, please contact Ben Bullock or use the discussion forum / Privacy policy

Book reviews Convert<br>Japanese<br>numbers Handwritten<br>kanji<br>recognition Stroke order<br>diagrams Convert<br>Japanese<br>units