I'm having some confusion on the potential form of Japanese verbs, specifically ichidan verbs. The sources I'm using for my learning tell me that I should replace 'ru' with 'rareru' or 'rarenai' (examples being 'taberareu' for 'can eat' and 'taberarenai' for 'can't eat'). I'm noticing this isn't always the case, however. The potential forms for 'miru' are 'mireru' and 'mirenai', the forms for 'hashiru' are 'hashireru' and 'hashirenai', and the negative potential form for 'uragiru' is 'uragiranai'. Clearly they don't all follow the rule of replacing the 'ru' with 'rareru'. Is there any way for me to be able to tell which ichidan verbs will follow the rule and which ones won't? Thank you all!

  • 1
    "hashiru" and "uragiru" are godan, not ichidan. But anyway, it sounds like you're asking about "ranuki kotoba" but did you encounter things like "mireru" in a learning resource or out in the real world?
    – Leebo
    Aug 21, 2023 at 14:19
  • Negative-potential of うらぎる is うらぎれない, not うらぎらない.
    – naruto
    Aug 21, 2023 at 17:59

1 Answer 1


Since you use term ichidan, I assume that you also heard godan.

Conclusive/Terminal forms of all ichidan verbs in modern Japanese end with -ru, but this does not mean that all verbs ending in ru belong to ichidan class. There are some verbs whose morphological stem ends in r, and only the following u is suffix of Conclusive/Terminal form. I use hyphen below to show boundary between stem and suffixes.

hashir-u and uragir-u are godan verbs. Therefore they allow formation of Potential forms with -eru: hashir-eru, uragir-eru.

Normal Potential forms of ichidan verbs (e.g. mi-ru, tabe-ru) have -rareru: mi-rareru, tabe-rareru.

In recent times in colloquial Japanese, shortened forms of Potential have developed. These forms have ra dropped from -rareru, resulting in -reru, so this grammatical phenomenon is called ら抜{ぬ}き (one of meanings of verb 抜{ぬ}く is "to omit, to skip").

For aforementioned ichidan verbs, Potential forms with ら抜{ぬ}き are: mi-reru, tabe-reru.

There are some pairs of homophonic verbs belonging to ichidan and godan classes. Examples:

i-ru "to exist" (and others), ir-u "to need" (and others)

ki-ru "to put on (cloths)", kir-u "to cut"

kae-ru "to change, to replace", kaer-u "to return"

They have different kanji spellings. Most forms of such verbs do not overlap (e.g. ki-masu versus kir-imasu).

If you heard about -areru suffix of godan verbs and if you heard that this suffix creates Passive form, then I inform that this suffix, possibly with literary/archaic nuance, can be used to create Potential. -rareru is variant of -areru suffix (-areru is used with godan verbs, -rareru is used with ichidan verbs). Both Passive and Potential are original functions of -(r)areru suffix, and Potential meaning of this suffix for godan verbs is now rarely used, but remains for ichidan verbs.

-eru is a different suffix and can be used only with godan verbs. Some centuries ago this suffix also had both Potential and Passive meaning.

In above explanation, for simplicity, hyphen is added only between stem of lexical verb and first suffix. In conjugation of verbs and adjectives in Japanese, there are often multiple suffixes glued together, usually in only one valid order. More correct segmentation of hashireru, mirareru, kirimasu and kirimasen would be: hashir-e-ru, mi-rare-ru, kir-i-mas-u, kir-i-mase-n.

  • Oh, the way I learned it was that any verb that ends with 'ru' and has an 'i' or 'e' immediately before the 'ru' was an ichidan verb. I understood that verbs like 'okuru (to send)' were godan verbs. hashiru and uragiru seemed to follow the ichidan verb conjugation when I tried them with other conjugation forms like past affirmative. Is there any way or rule to tell which 'iru' or 'eru' verbs will be ichidan or godan, or is it just a matter of already knowing which one is which?
    – Derek Kwon
    Aug 21, 2023 at 16:53
  • @DerekKwon Past form of godan -ru verbs ends with -tta (e.g. hashitta, uragitta, kitta, kaetta), while ichidan verbs have form ending with -ta (e.g. kita, kaeta). First t in -tta is result of elision of vowel i and assimilation of r to following t, which occurred in Late Middle Japanese (if verb uragiru existed at that time, then development of that form of that verb was: uragiritaruuragittaruuragitta).
    – Arfrever
    Aug 21, 2023 at 18:31
  • @DerekKwon You have to learn which verbs are ichidan or godan. By grepping in my dictionary, it seems that about 88% of ru verbs belong to ichidan class (2261 versus 320 godan ru verbs). If you know rules of morphology of Japanese language, then another strategy is to learn stems of verbs (e.g. to learn verb ki- "to put on (cloths)", and verb kir- "to cut"). Then only few irregular verbs remain where you have to learn irregularities (verbs ko- (来る) and se- (する) are relatively more irregular, and few other verbs have about one or two irregular forms).
    – Arfrever
    Aug 21, 2023 at 18:50
  • @DerekKwon For verbs such as iu, kau, stem can be assumed to end with w which automatically disappears before u, so they have forms such as [iw- + -u → |iwu| → iu, iw- + -anaiiwanai, ...], [kaw- + -u → |kawu| → kau, kaw- + -anaikawanai, ...]. (Before 10th century, stem of these verbs ended in p, and therefore Conclusive/Terminal forms were ipu, kapu (negative form had different suffix).)
    – Arfrever
    Aug 21, 2023 at 19:05
  • Thank you! You've been a great help
    – Derek Kwon
    Aug 21, 2023 at 22:23

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