In English, "the door opened" and "I opened the door" use the same verb. Japanese doesn't work that way — opening by itself and being opened by someone use two different verbs:
| Japanese | Type | Meaning |
|---|---|---|
| ドアが開いた。 | Intransitive (自動詞) | The door opened (by itself). |
| ドアを開けた。 | Transitive (他動詞) | (Someone) opened the door. |
Intransitive verbs describe "things happening naturally"; transitive verbs describe "someone making things happen." This distinction directly determines which particle to use.
Core Rule: Intransitive = が, Transitive = を
| Intransitive (自動詞) | Transitive (他動詞) | |
|---|---|---|
| Particle | Subject + が | Object + を |
| Focus | Result/state | Action/agent |
| Example | ドアが開いた | ドアを開けた |
Intransitive = no one acts, it happens naturally → only a subject (が) Transitive = someone acts to cause it → agent + object (を)
Common Transitive/Intransitive Pairs
Japanese transitive and intransitive verbs often come in pairs — same root, different endings:
| Intransitive (が) | Transitive (を) | Meaning |
|---|---|---|
| 開く (あく) | 開ける (あける) | open |
| 閉まる (しまる) | 閉める (しめる) | close |
| 乾く (かわく) | 乾かす (かわかす) | dry |
| 移る (うつる) | 移す (うつす) | move |
| 枯れる (かれる) | 枯らす (からす) | wither |
| 捕まる (つかまる) | 捕まえる (つかまえる) | catch |
| 揺れる (ゆれる) | 揺らす (ゆらす) | shake |
| 破れる (やぶれる) | 破る (やぶる) | break/tear |
| 儲かる (もうかる) | 儲ける (もうける) | profit |
Ending Patterns (not absolute, but useful)
| Intransitive ending | Transitive ending | Example |
|---|---|---|
| -る | -す | 移る / 移す |
| -れる | -る | 破れる / 破る |
| -く | -かす | 乾く / 乾かす |
| -まる | -める | 閉まる / 閉める |
| -かる | -ける | 儲かる / 儲ける |
Practical Examples
Intransitive: Things Happen Naturally
| Example | Note |
|---|---|
| 犯人が捕まった。 The criminal was caught. | Intransitive 捕まる → no need to say who caught them |
| 火山の爆発で大地が揺れる。 The ground shakes from the volcanic eruption. | Intransitive 揺れる → natural phenomenon |
| 兄が恋に破れた。 My brother failed in love. | Intransitive 破れる → natural outcome |
| 洗濯物が乾いた。 The laundry dried. | Intransitive 乾く → dried on its own |
Note 犯人が捕まった — in English we say "was caught" (passive), but Japanese uses an intransitive verb. Many Japanese intransitive verbs inherently carry passive meaning without needing passive form.
Transitive: Someone Acts
| Example | Note |
|---|---|
| 娘がドライヤーで髪を乾かしている。 My daughter is blow-drying her hair. | Transitive 乾かす → someone causes drying |
| 計画を実行に移します。 Put the plan into action. | Transitive 移す → someone moves it |
| この植物を枯らさないでください。 Please don't let this plant wither. | Transitive 枯らす → someone causes withering |
| お金を儲けました。 Made money. | Transitive 儲ける → someone earns it |
Idiomatic Expressions Using Transitivity
Japanese has clever idioms that exploit the transitive/intransitive distinction:
| Idiom | Literal | Actual Meaning |
|---|---|---|
| 筆が立つ | The brush stands up (intransitive) | Writes well / has good prose |
| 顔を立てる | Stand someone's face up (transitive) | Give someone face / respect |
| 目がつく | Eyes land there (intransitive) | Eye-catching, conspicuous |
広告を目につくところに貼りましょう。 → Let's put the ad somewhere eye-catching.
今日はあなたの顔を立てましょう。 → Today I'll give you face (defer to you).
がまんする: A Transitive That Looks Intransitive
がまんする (endure/put up with) is transitive — the thing you endure takes を:
ナナコはかばんを安物でがまんした。 → Nanako settled for a cheap bag.
そなえる: Prepare/Guard Against
備える (そなえる) is transitive, meaning "prepare for":
毎日の事態に備えて、次の手を打っておこう。 → Let's prepare countermeasures for daily situations.
に marks "what you're preparing against"; 備える is actively taking action.
Summary
- Intransitive = happens naturally (が); Transitive = someone causes it (を)
- Japanese pairs share roots but differ in endings (-る/-す, -れる/-る, -く/-かす, etc.)
- Intransitive verbs can express passive meaning (犯人が捕まった = criminal was caught)
- Wrong verb type → wrong particle → unnatural sentence
- Idioms use the distinction cleverly (筆が立つ vs 顔を立てる)
Practice Questions
Q1. 「洗濯物が乾いた」and「髪を乾かした」— what verb type is each and why?
Show answer
- 乾いた (intransitive) → laundry dried on its own, no agent → subject with が
- 乾かした (transitive) → someone used a dryer to cause drying → object with を
Q2. Why doesn't 「犯人が捕まった」 need passive form?
Show answer
Because 捕まる is already intransitive and inherently means "get caught." Many Japanese intransitive verbs carry passive nuance naturally — no need to add -られる. English translates it as passive ("was caught"), but Japanese just uses intransitive + が.
Q3. Are 「筆が立つ」 and 「顔を立てる」 intransitive or transitive?
Show answer
- 筆が立つ → Intransitive (が + 立つ) → the brush "stands up on its own" = writes well
- 顔を立てる → Transitive (を + 立てる) → someone "stands the face up" = gives face