Grammar › Outcome & Result
たが最後 — “once you do X, (inevitably Y happens)”
Says that a single action locks in an unavoidable, often unwelcome, chain of consequences
Past-plain verb + が最後 says that the moment a particular action is taken, some (usually negative or irreversible) consequence is guaranteed to follow — “once you do X, that's it — Y is inevitable.” It carries a sense of a point of no return.
How to form it
| Pattern | Example |
|---|---|
| Past plain + が最後 | 一度眠ったが最後、朝まで起きない — Once he falls asleep, that's it — he won't wake until morning |
Example sentences
| Japanese | Reading | Meaning |
|---|---|---|
| このボタンを押したが最後、二度と後戻りはできない。 | このぼたんをおしたがさいご、にどとあともどりはできない。 konobotanwooshitagasaigo、nidotoatomodorihadekinai。 | Once you press this button, there's no going back, ever. |
| 彼は話し始めたが最後、誰にも止められない。 | かれははなしはじめたがさいご、だれにもとめられない。 karehahanashihajimetagasaigo、darenimotomerarenai。 | Once he starts talking, nobody can stop him. |
| 一度サボり癖がついたが最後、なかなか元には戻れない。 | いちどさぼりぐせがついたがさいご、なかなかもとにはもどれない。 ichidosaborigusegatsuitagasaigo、nakanakamotonihamodorenai。 | Once a habit of slacking off sets in, it's hard to shake. |
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Watch out
が最後 always signals an unavoidable, usually unwelcome, chain reaction — it isn't a neutral “after doing X”; save it for situations that really do function as a point of no return.