Every Japanese verb belongs to one of two regular classes — 五段 or 一段 — plus the two irregulars. For most verbs the ending gives the class away: anything ending in う, く, ぐ, す, つ, ぬ, ぶ, or む is 五段, no ambiguity. But verbs ending in る are the exception, and they are the single nastiest problem in the whole conjugation system, because a る-ending verb can be either class, and the two conjugate completely differently. 帰る is 五段 (帰らない, 帰ります); 見る is 一段 (見ない, 見ます). This page gives you the heuristic that handles most cases and the one test that never fails.
Why る-verbs are ambiguous and nothing else is
A 一段 verb, by definition, must have its stem end in an い-row or え-row syllable followed by る: 見る (mi-ru), 食べる (tabe-ru), 起きる (oki-ru), 寝る (ne-ru). No 一段 verb can end in any other vowel + る. A 五段 verb ending in る, however, can have any vowel before the る: 取る (to-ru), 作る (tsuku-ru), 乗る (no-ru) — but also 帰る (kae-ru) and 走る (hashi-ru), which end in え and い just like 一段 verbs do. So the two classes only ever collide in the -iru / -eru zone. That collision is the entire problem, and the rest of this page is about resolving it.
The heuristic: -aru, -uru, -oru are always 五段
Start with the easy 60%. If the syllable before る is in the あ-row, う-row, or お-row — that is, the verb ends in -aru, -uru, or -oru — it is 五段, guaranteed, with zero exceptions. There is no such thing as a 一段 verb ending in these sounds, because 一段 stems can only end in い or え.
| Ending | Examples | Class |
|---|---|---|
| -aru | 分かる (wakaru), 始まる (hajimaru), ある (aru), 上がる (agaru) | 五段 always |
| -uru | 作る (tsukuru), 送る (okuru), 降る (furu) | 五段 always |
| -oru | 取る (toru), 乗る (noru), 通る (tōru) | 五段 always |
So the moment you see -aru / -uru / -oru, stop thinking — it's 五段. All the difficulty is concentrated in the remaining case.
The hard zone: -iru and -eru are usually 一段, but not always
If the verb ends in -iru or -eru (an い-row or え-row syllable + る), the default guess is 一段 — most such verbs are: 見る, 食べる, 起きる, 寝る, 教える, 開ける, 借りる, 信じる. Guess 一段 and you will be right most of the time.
But a notorious set of very high-frequency verbs end in -iru / -eru and are 五段 anyway. These are the renegades you must memorize, because they are common and there is no way to predict them from spelling.
| Verb | Reading | Meaning | Negative (五段!) |
|---|---|---|---|
| 帰る | kaeru | to go/come home | 帰らない (kaeranai) |
| 入る | hairu | to enter | 入らない (hairanai) |
| 走る | hashiru | to run | 走らない (hashiranai) |
| 知る | shiru | to know | 知らない (shiranai) |
| 切る | kiru | to cut | 切らない (kiranai) |
| 要る | iru | to need | 要らない (iranai) |
| 限る | kagiru | to limit | 限らない (kagiranai) |
| しゃべる | shaberu | to chat, talk | しゃべらない (shaberanai) |
| 減る | heru | to decrease | 減らない (heranai) |
| 蹴る | keru | to kick | 蹴らない (keranai) |
| 滑る | suberu | to slip, slide | 滑らない (suberanai) |
| 握る | nigiru | to grip, grasp | 握らない (nigiranai) |
| 参る | mairu | to go/come (humble) | 参らない (mairanai) |
The one reliable test: form the negative
When you are unsure — or when you meet a new verb in the wild — there is a test that never lies: form the plain negative and listen for らない.
- If the negative is らない (stem's る → ら, plus ない), it is 五段: 帰る → 帰らない, 切る → 切らない.
- If the negative is just the stem (drop る) + ない, keeping the い/え vowel, it is 一段: 見る → 見ない, 食べる → 食べない.
疲れたから、今日は早く帰る。
tsukareta kara, kyō wa hayaku kaeru
I'm tired, so I'm going home early today. (帰る — dictionary)
仕事が終わるまで帰らない。
shigoto ga owaru made kaeranai
I'm not going home until work is done. (帰らない — 五段 negative confirms the class)
最近、あまりテレビを見ない。
saikin, amari terebi o minai
I don't really watch TV lately. (見ない — 一段 negative)
The same test works on masu-forms and potentials if you already know them (五段 帰ります・帰れる vs 一段 見ます・見られる), but the negative is the cleanest because the らない ending is so audibly distinct.
The homophone traps: same sound, different class
The reason this matters so much is that Japanese is full of minimal pairs — verbs pronounced identically in the dictionary form but belonging to different classes, so they conjugate differently. Getting the class wrong doesn't just sound off; it can produce the wrong verb entirely.
| Sound | 五段 verb | negative | 一段 verb | negative |
|---|---|---|---|---|
| kaeru | 帰る (go home) | 帰らない | 変える (change) | 変えない |
| kiru | 切る (cut) | 切らない | 着る (wear) | 着ない |
| iru | 要る (need) | 要らない | 居る (exist) | いない |
| neru | 練る (knead) | 練らない | 寝る (sleep) | 寝ない |
このハサミ、よく切れる。でも硬いものは無理に切らないほうがいい。
kono hasami, yoku kireru. demo katai mono wa muri ni kiranai hō ga ii
These scissors cut well, but you shouldn't force them through hard things. (切る is 五段 — 切らない)
寒いから、上着を着ないと風邪をひくよ。
samui kara, uwagi o kinai to kaze o hiku yo
It's cold, so you'll catch a cold if you don't wear a jacket. (着る is 一段 — 着ない)
パスポートは要らないけど、身分証は要る。
pasupōto wa iranai kedo, mibunshō wa iru
You don't need a passport, but you do need ID. (要る is 五段 — 要らない)
Common mistakes
❌ 疲れたから、もう帰ない。
Wrong — 帰る is 五段 despite ending in -eru. The negative is 帰らない, not the 一段-style ×帰ない.
✅ 疲れたから、もう帰らない。
tsukareta kara, mō kaeranai
I'm tired, so I'm not going anymore / not heading home yet.
❌ その言葉の意味を知ない。
Wrong — 知る is 五段, so 'I don't know' is 知らない, not ×知ない. This is one of the most common learner errors.
✅ その言葉の意味を知らない。
sono kotoba no imi o shiranai
I don't know what that word means.
❌ お金はもう要ない。
Wrong — 要る (to need) is 五段, so the negative is 要らない, not ×要ない.
✅ お金はもう要らない。
okane wa mō iranai
I don't need any more money.
❌ 毎朝、公園を走ます。
Wrong — 走る is 五段, so the polite form is 走ります (hashirimasu), not the 一段-style ×走ます.
✅ 毎朝、公園を走ります。
maiasa, kōen o hashirimasu
I run in the park every morning.
Key takeaways
- Only る-verbs are class-ambiguous; every other ending (う・く・ぐ・す・つ・ぬ・ぶ・む) is automatically 五段.
- -aru, -uru, -oru verbs are always 五段 — no exceptions, no thinking.
- -iru, -eru verbs default to 一段, but a short list of common renegades (帰る・入る・走る・知る・切る・要る・限る・しゃべる…) is 五段 and must be memorized.
- The reliable test is the negative: らない = 五段, plain stem + ない = 一段.
- Beware homophone pairs (帰る／変える, 切る／着る, 要る／居る) where the same sound splits across classes.
Now practice Japanese
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Start learning Japanese→Related Topics
- 取る: Full 五段 -る ParadigmN5 — The complete conjugation of 取る, the model 五段 verb ending in -る (not to be confused with a 一段 る-verb), whose te-form and past take the small-っ 促音便 (取って・取った).
- 食べる: Full 一段 ParadigmN5 — The complete eleven-form paradigm of 食べる (taberu) — the model 一段 verb whose every form is just 'drop る, add the ending' with zero sound change, and whose potential, passive, and honorific are all the identical 食べられる.
- Common Verbs by Class: Quick ListN5 — A cheat-sheet that sorts high-frequency verbs into 五段 / 一段 / irregular so you can classify a verb before you conjugate it — with the -いる／-える 五段 traps flagged so you never write ×帰ない for 帰らない.
- Model Verbs by Class: IndexN5 — The one-stop lookup hub for the Regular Paradigms subgroup — a master table anchoring each verb ending to exactly one worked model verb (会う・書く・泳ぐ・話す・待つ・死ぬ・遊ぶ・読む・取る・食べる・する・来る), its class, and its te-form, with a link to each full paradigm page.
- Negative ない: Formation TableN4 — How to build the plain negative 〜ない across every class — the 五段 あ-row stem (with the わ trap), 一段 drop-る, the irregulars, and the suppletive ある → ない.