Verb たが最後 (〜ta ga saigo)
Explanation
Emphasizes 'once something happens, there is no going back'; 'once', 'as soon as', etc.
Formation
Verb-casual, past (た form) + が最後
Detailed Explanation
The 〜たが最後 grammar point indicates that once an action is taken or event occurs, some (often irreversible) consequence follows. In English, it can be translated as 'once', 'as soon as', or 'the moment that...'.
Examples
彼が一度怒ったが最後、誰も彼を止めることはできません。
Kare ga ichido okotta ga saigo, dare mo kare o tomeru koto wa dekimasen.
Once he gets angry, no one can stop him.
このゲームを始めたが最後、一晩中やり続けた。
Kono gēmu o hajimeta ga saigo, hitobanjū yari tsuzuketa.
As soon as I started this game, I played it all night.
彼女が部屋を出たが最後、二度と戻ってこなかった。
Kanojo ga heya o deta ga saigo, nido to modotte konakatta.
The moment she left the room, she never came back.
私がその橋を渡ったが最後、それが最後の別れだった。
Watashi ga sono hashi o watatta ga saigo, sore ga saigo no wakare datta.
Once I crossed that bridge, it was our final goodbye.
Grammar content sourced from hanabira.org.