Chinese speakers get half their Japanese vocabulary free through kanji. But there's one area where kanji doesn't just fail to help — it actively works against you: transitive vs. intransitive verb pairs.
One Chinese word, two Japanese verbs
The Chinese 開 covers two situations with a single word: "the door opened" (the door does it itself) and "I opened the door" (I act on it). Same 開, disambiguated by context.
Japanese won't let you. "The door opened" is 開く (aku); "I opened the door" is 開ける (akeru) — two different verbs. Japanese forces "the thing changed on its own" and "someone changed the thing" into separate words. That split simply doesn't exist in Chinese, which is why Chinese speakers so often miss the pair entirely, or grab the wrong half.
In grammar terms: an intransitive verb describes the subject changing on its own, no agent involved (the door opened). A transitive verb describes someone acting on something (opening the door).
を and が give the answer away
You don't have to memorize which is which — the particle in the sentence tells you:
- Thing followed by を → transitive (someone's doing it). ドアを開ける (I open the door).
- Thing followed by が → intransitive (it happens on its own). ドアが開く (the door opens).
を is the signal that "someone is acting on this." When you read 〜を in Japanese, you know it's a transitive verb with an agent behind it. It's the most practical litmus test for the transitive/intransitive split.
Four patterns (tendencies, not laws)
The pairs aren't random — the endings carry the logic. Every rule below checks out against everyday verbs:
Rule 1: verbs ending in 〜す are almost always transitive. 出す, 消す, 落とす, 起こす, 直す, 壊す, 汚す… See す and you can nearly always assume "someone is doing this." Highest hit rate of the four.
Rule 2: in a paired 〜aru / 〜eru set, aru is intransitive, eru is transitive. 始まる (intr) / 始める (tr), 決まる / 決める, 集まる / 集める, 閉まる / 閉める, 上がる / 上げる, 変わる / 変える. Mnemonic: aru = Automatic (happens by itself).
Rule 3: verbs ending in 〜れる lean intransitive. 壊れる, 割れる, 折れる, 濡れる, 汚れる — all "the thing ends up that way," no one responsible.
Rule 4: in a paired 〜eru (tr) / 〜u (intr) set, the e-row one is transitive. 開ける / 開く, 付ける / 付く, 立てる / 立つ, 続ける / 続く.
High-frequency pairing table
| Core idea | Transitive (を) | Intransitive (が) |
|---|---|---|
| open | 開ける akeru | 開く aku |
| close | 閉める shimeru | 閉まる shimaru |
| begin | 始める hajimeru | 始まる hajimaru |
| put out / go out | 出す dasu | 出る deru |
| put in / enter | 入れる ireru | 入る hairu |
| turn off / go out | 消す kesu | 消える kieru |
| decide | 決める kimeru | 決まる kimaru |
| raise / rise | 上げる ageru | 上がる agaru |
| drop / fall | 落とす otosu | 落ちる ochiru |
| stand | 立てる tateru | 立つ tatsu |
| gather | 集める atsumeru | 集まる atsumaru |
| stop | 止める tomeru | 止まる tomaru |
Two things to handle separately
The rules are there to save effort, not to replace all memory. Two cases deserve extra care:
When the reading changes entirely, just memorize it. 入れる (ireru) / 入る (hairu) isn't a tidy ending swap — both readings differ, so you learn it outright. There aren't many like this, but they're all high-frequency.
The てある vs ている sense trap. 窓が開いている ("the window is open," just describing a state) versus 窓が開けてある ("the window has been opened," stressing that someone did it on purpose). Pick the wrong transitivity and the whole nuance tilts. This is a frequent N3–N2 reading point, worth drilling on its own.
How to practice
In one line: never learn a verb alone — always learn the pair, each with its own を / が example. When you study 集める, study 集まる at the same time, and build a sentence for each: 先生が学生を集める / 学生が集まる. Learned as a pair, they won't get crossed when you reach for them.
To sweep them systematically, use vocab mode, where we tag the pairing in the transitive_pair field; or use full-text search to check any verb and confirm whether it's transitive or intransitive.
Transitive/intransitive pairs are one of the few places in Japanese where kanji can't carry you — but it isn't a tangle. It has patterns, and it hands you を / が as a free tell. Absorb the rules and you'll find the steepest-looking slope actually comes with steps built in.