Once you accept that Japanese pairs verbs into intransitive and transitive twins, the obvious next question is: can I predict which is which from the shape of the word? The answer is a frustrating partly. The pairs cluster into a handful of recurring sound patterns — 始まる／始める, 閉まる／閉める, 割れる／割る, 壊れる／壊す — and spotting the pattern speeds up learning enormously. But the patterns overlap and contradict each other, so no single rule ever reaches 100%. This page lays out the families that actually pay off, gives you the frequent members to bank as vocabulary, and tells you honestly where the tendencies break down.
Why there's no clean rule
English gives you no hint — open, break, start look identical whether an agent is involved or not. Japanese hides partial clues in the verb endings, the residue of ancient derivational suffixes. Over a thousand years those suffixes eroded and cross-bred, leaving tendencies rather than laws. So the working strategy is: learn the frequent pairs as vocabulary, and use the patterns below as memory scaffolding and educated guesses — never as a guarantee.
Family 1: -aru (intr) / -eru (tr)
The changing thing ends in -aる; the doer's verb ends in -eる. Extremely common and very regular-feeling.
| 自動詞 -aる | 他動詞 -eる | Meaning |
|---|---|---|
| 始まる (hajimaru) | 始める (hajimeru) | begin |
| 閉まる (shimaru) | 閉める (shimeru) | close |
| 止まる (tomaru) | 止める (tomeru) | stop |
| 決まる (kimaru) | 決める (kimeru) | be decided / decide |
| 上がる (agaru) | 上げる (ageru) | go up / raise |
| 集まる (atsumaru) | 集める (atsumeru) | gather |
| 見つかる (mitsukaru) | 見つける (mitsukeru) | be found / find |
会議の日程がやっと決まった。
kaigi no nittei ga yatto kimatta
The date for the meeting has finally been decided. (intransitive)
会議の日程を来週までに決めます。
kaigi no nittei o raishū made ni kimemasu
I'll decide the meeting date by next week. (transitive)
Family 2: -u (intr) / -eru (tr)
The intransitive keeps a plain -u ending; the transitive adds -eる. This is the 開く／開ける family.
| 自動詞 -u | 他動詞 -eる | Meaning |
|---|---|---|
| 開く (aku) | 開ける (akeru) | open |
| 付く (tsuku) | 付ける (tsukeru) | attach / turn on |
| 並ぶ (narabu) | 並べる (naraberu) | line up |
| 進む (susumu) | 進める (susumeru) | advance |
| 育つ (sodatsu) | 育てる (sodateru) | grow up / raise |
桜がきれいに並んでいる。
sakura ga kirei ni narande iru
The cherry trees are lined up beautifully. (intransitive)
机を廊下に並べてください。
tsukue o rōka ni narabete kudasai
Please line the desks up in the hallway. (transitive)
Family 3: -eru (intr) / -u (tr)
Now it flips: the -eる verb is the intransitive and the plain -u verb is the transitive. This is the mirror image of Family 2, which is exactly why the "-eru = transitive" hunch is a trap.
| 自動詞 -eる | 他動詞 -u | Meaning |
|---|---|---|
| 割れる (wareru) | 割る (waru) | break / shatter |
| 切れる (kireru) | 切る (kiru) | be cut / cut |
| 折れる (oreru) | 折る (oru) | snap / fold |
| 破れる (yabureru) | 破る (yaburu) | tear |
| 焼ける (yakeru) | 焼く (yaku) | burn / grill |
ズボンが破れてしまった。
zubon ga yaburete shimatta
My trousers got torn. (intransitive)
子どもが漫画のページを破った。
kodomo ga manga no pēji o yabutta
The kid tore a page of the comic. (transitive)
Family 4: -reru (intr) / -su (tr)
The intransitive ends in -れる, the transitive in -す. Clean and reliable, and the -す confirms the transitive.
| 自動詞 -れる | 他動詞 -す | Meaning |
|---|---|---|
| 壊れる (kowareru) | 壊す (kowasu) | break down / break |
| 倒れる (taoreru) | 倒す (taosu) | fall over / knock down |
| 汚れる (yogoreru) | 汚す (yogosu) | get dirty / make dirty |
| 離れる (hanareru) | 離す (hanasu) | separate |
台風で街路樹が倒れた。
taifū de gairoju ga taoreta
A street tree fell over in the typhoon. (intransitive)
レスラーが相手を倒した。
resurā ga aite o taoshita
The wrestler knocked his opponent down. (transitive)
Family 5: -ru (intr) / -su (tr) and other -す transitives
A grab-bag of pairs where the transitive again lands on -す — the single most dependable signal in the whole system.
| 自動詞 | 他動詞 -す | Meaning |
|---|---|---|
| 直る (naoru) | 直す (naosu) | be fixed / fix |
| 回る (mawaru) | 回す (mawasu) | spin / turn |
| 戻る (modoru) | 戻す (modosu) | return / put back |
| 出る (deru) | 出す (dasu) | come out / take out |
| 消える (kieru) | 消す (kesu) | go out / erase |
| 落ちる (ochiru) | 落とす (otosu) | fall / drop |
| 起きる (okiru) | 起こす (okosu) | get up / wake (someone) |
スマホが階段から落ちた。
sumaho ga kaidan kara ochita
My phone fell down the stairs. (intransitive)
財布を落とさないように気をつけて。
saifu o otosanai yō ni ki o tsukete
Be careful not to drop your wallet. (transitive)
Family 6: the odd couple 入る / 入れる
入る (はいる, go in, intransitive) and 入れる (いれる, put in, transitive) are so frequent they deserve their own callout. Note the reading shift — the intransitive is hairu, the transitive ireru — and that the pair fits none of the tidy patterns above.
お風呂にお湯が入っている。
o-furo ni o-yu ga haitte iru
There's hot water in the bath. (intransitive)
コーヒーに砂糖を入れますか。
kōhī ni satō o iremasu ka
Do you take sugar in your coffee? (transitive)
The trap: not every -eru verb is transitive
The most dangerous over-generalization is "-eる means transitive." It fails constantly. First, whole families (2 vs 3 above) put -eる on opposite sides. Second, a big group of -eる verbs are intransitive by nature and have no transitive partner at all — they express spontaneous perception or change:
| Verb | Meaning | Note |
|---|---|---|
| 見える (mieru) | be visible | spontaneous — not "見る see" transitivized |
| 聞こえる (kikoeru) | be audible | spontaneous — not "聞く hear" |
| 疲れる (tsukareru) | get tired | intransitive, no を partner |
| 晴れる (hareru) | clear up (weather) | intransitive only |
ここから富士山がよく見える。
koko kara fujisan ga yoku mieru
You can see Mt. Fuji clearly from here. (spontaneous intransitive)
Inventing a partner is the other half of the trap: there's no ×見えす or ×疲らす to match these. When you're unsure whether a pair even exists, check rather than guess.
Common Mistakes
❌ 窓が割ってしまった。
Wrong member — 割る is transitive (someone breaks it). For 'the window broke by itself,' use the intransitive 割れる: 窓が割れてしまった.
✅ 窓が割れてしまった。
mado ga warete shimatta
The window broke (unfortunately).
❌ 富士山を見えました。
Wrong — 見える is a spontaneous intransitive ('be visible') and takes が, not を. Don't treat -eる as automatically transitive.
✅ 富士山が見えました。
fujisan ga miemashita
Mt. Fuji was visible.
❌ パソコンを直った。
Wrong member — 直る is intransitive ('be fixed'). To say someone fixed it, use 直す: パソコンを直した.
✅ パソコンが直った。
pasokon ga naotta
The computer got fixed.
❌ 砂糖が入れました。
Wrong — 入れる is transitive ('put in') and needs を; the intransitive 'go in' is 入る (hairu): 砂糖が入っています.
✅ 砂糖を入れました。
satō o iremashita
I put sugar in.
Key Takeaways
- The pairs cluster into recurring shapes (-aる/-eる, -u/-eる, -eる/-u, -れる/-す, -ru/-す), but the shapes overlap and contradict.
- The most reliable single signal: -す = transitive. In an -aる/-eる pair, the -aる side is intransitive.
- Never assume -eる is transitive — Families 2 and 3 disagree, and 見える・聞こえる・疲れる are intransitive with no partner.
- Learn the frequent pairs as vocabulary; use the patterns to guess and to remember, not as rules.
Now practice Japanese
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Start learning Japanese→Related Topics
- 自動詞 / 他動詞: Transitivity PairsN4 — Why Japanese splits into intransitive verbs (subject が, happens by itself) and transitive verbs (object を, someone does it) where English usually gets by with a single verb.
- Intransitive + ている: Resultant StateN3 — How change-of-state intransitive verbs plus ている describe a lingering resultant state — 'the door is open,' 'the light is on' — rather than an action in progress.
- Transitive + てある: Prepared StateN3 — How a transitive verb plus てある marks a state that someone deliberately produced and left in place — 'the door has been (purposely) left open,' 'a reservation has been made' — versus the agentless ている.