The Three Verb Groups五段・一段・不規則
Every Japanese verb belongs to one of three groups: godan (五段, Group I), ichidan (一段, Group II), or irregular (不規則). Knowing which group a verb belongs to is the single most important thing for conjugation, because each group follows different rules. Get this wrong and every conjugation you build will be wrong too.
Every Japanese verb belongs to one of three groups: godan (五段, Group I), ichidan (一段, Group II), or irregular (不規則). Knowing which group a verb belongs to is the single most important thing for conjugation, because each group follows different rules. Get this wrong and every conjugation you build will be wrong too.
Why verb groups matter
Japanese conjugation is not random. Once you know a verb’s group, you can predict every single form it takes: polite, negative, past, potential, passive, causative, and more. The three groups are sometimes called Group I / Group II / Group III, or u-verbs / ru-verbs / irregular. In this reference we use the Japanese terms godan (五段, "five-step"), ichidan (一段, "one-step"), and irregular (不規則).
Group I: Godan (五段) verbs
Godan verbs are the largest group. Their dictionary form ends in one of the consonant-row kana: -u, -ku, -gu, -su, -tsu, -nu, -bu, -mu, -ru. When conjugated, the final kana shifts across the five vowel rows (あ段, い段, う段, え段, お段) — hence the name "five-step." If a verb ends in -ru but the vowel before -ru is a, u, or o, it is almost always godan.
Common godan verbs
書く (kaku, to write), 話す (hanasu, to speak), 待つ (matsu, to wait), 死ぬ (shinu, to die), 飛ぶ (tobu, to fly), 読む (yomu, to read), 作る (tsukuru, to make), 買う (kau, to buy), 泳ぐ (oyogu, to swim).
The "false ru" trap
Some verbs look like ichidan because they end in -eru or -iru, but are actually godan. The most notorious ones: 帰る (kaeru, to return), 切る (kiru, to cut), 走る (hashiru, to run), 知る (shiru, to know), 入る (hairu, to enter). You must memorize these exceptions — there are roughly 30 of them, and they appear constantly.
Group II: Ichidan (一段) verbs
Ichidan verbs always end in -iru or -eru in dictionary form. To conjugate, you simply drop -ru and attach the suffix — no vowel shifting. This makes them the easiest group. The name "one-step" refers to the fact that the stem vowel never changes.
Common ichidan verbs
食べる (taberu, to eat), 見る (miru, to see), 起きる (okiru, to wake up), 寝る (neru, to sleep), 着る (kiru, to wear), 出る (deru, to go out), 開ける (akeru, to open), 教える (oshieru, to teach), 考える (kangaeru, to think).
Group III: Irregular verbs
Japanese has only two truly irregular verbs: する (suru, to do) and 来る (kuru, to come). However, する attaches to hundreds of nouns to form compound verbs (勉強する, 料理する, 運動する), so you encounter it constantly. These two verbs each have unique conjugation patterns that must be memorized individually. The good news: once you learn these two, you’re done with irregulars forever.
How to identify a verb’s group
Follow this decision tree: (1) Is it する or 来る? → Irregular. (2) Does it end in -iru or -eru? → Probably ichidan, but check the false-ru exception list. (3) Does it end in any other -u sound? → Godan. This covers 99% of cases. When in doubt, look it up in a dictionary — Japanese dictionaries mark verbs as 五段 or 一段.
Verb group identification at a glance
| Group | Ending | Example | Dictionary | Stem |
|---|---|---|---|---|
| Godan (五段) | -u row kana | 書く | kaku | kak- |
| Godan | -u row kana | 話す | hanasu | hanas- |
| Godan | -u row kana | 待つ | matsu | mat- |
| Godan | -u row kana | 読む | yomu | yom- |
| Godan | -u row kana | 買う | kau | ka(w)- |
| Godan (false ru) | -iru / -eru | 帰る | kaeru | kaer- |
| Ichidan (一段) | -iru / -eru | 食べる | taberu | tabe- |
| Ichidan | -iru / -eru | 見る | miru | mi- |
| Ichidan | -iru / -eru | 起きる | okiru | oki- |
| Irregular (不規則) | する | する | suru | sh- / s- |
| Irregular | 来る | 来る | kuru | k- / ko- |
Example sentences
毎朝コーヒーを飲む。
Maiasa koohii o nomu.
I drink coffee every morning.
飲む is godan (-mu ending)
昨日新しいレストランで食べた。
Kinou atarashii resutoran de tabeta.
I ate at a new restaurant yesterday.
食べる is ichidan (drop -ru, add -ta)
来週から日本語を勉強する。
Raishuu kara nihongo o benkyou suru.
I’ll start studying Japanese from next week.
勉強する is irregular (する compound)
友達が明日こっちに来る。
Tomodachi ga ashita kocchi ni kuru.
My friend is coming here tomorrow.
来る is irregular
彼女は毎日走っている。
Kanojo wa mainichi hashitte iru.
She runs every day.
走る is godan (false -ru verb!)
窓を開けてもいいですか。
Mado o akete mo ii desu ka.
May I open the window?
開ける is ichidan
Common mistakes
帰りる (kaeriru)
帰る (kaeru)
帰る is godan, not ichidan. Its stem is kaer-, so the negative is 帰らない (kaeranai), not 帰ない.
食ばない (tabAnai)
食べない (tabenai)
食べる is ichidan. Drop -ru to get the stem 食べ-, then add -ない. Godan rules don’t apply here.
しない → すらない
しない (shinai)
する is irregular. Its negative is しない, not すらない. There is no pattern to predict it — just memorize it.
切れない (kirenai) for "can’t cut"
切らない (kiranai) for "don’t cut" / 切れない for potential
切る (kiru, to cut) is godan. 切らない is the plain negative. 切れない is the potential negative ("can’t cut"). Mixing these up is caused by confusing 切る with the ichidan 着る (kiru, to wear).
Frequently asked questions
How many godan verbs end in -iru or -eru (the "false ru" verbs)?
There are roughly 30 common ones. The most important to memorize: 帰る, 切る, 走る, 知る, 入る, 要る, 限る, 握る, 喋る, 蹴る. Beyond the top 30 you’ll rarely encounter them, and a dictionary will clarify any edge cases.
Are there really only two irregular verbs in Japanese?
Strictly yes — する and 来る are the only verbs with truly unpredictable conjugation patterns. However, する compounds (勉強する, 料理する, etc.) all follow the する pattern, giving you hundreds of "irregular" verbs in practice. Some textbooks also treat いく as semi-irregular because its て form is いって (not いいて), but its other forms follow godan rules perfectly.
What’s the fastest way to identify a verb’s group?
Check the ending. If it ends in anything other than -iru/-eru, it’s godan. If it ends in -iru/-eru, it’s probably ichidan, but check the false-ru exception list. If it’s する or 来る, it’s irregular. With practice, you’ll identify groups instantly without thinking.
What group does 食べる belong to?