What it means
途端に expresses that a second event happened immediately after the first event, often with a sudden or unexpected result. It follows a verb in the ta-form and focuses on the exact moment when the first action or change was completed. The event after 途端に is commonly outside the speaker’s control or something that occurred unexpectedly.
Usage note
途端に is normally used with a completed event and is not suitable for ordinary sequences that happen gradually or according to a planned schedule. The construction itself has no separate polite form; politeness is shown by the predicate at the end of the sentence.
How to use it
係員がドアを開けた途端に、冷たい風が部屋に入ってきました。
As soon as the staff member opened the door, a cold wind came into the room.
係員がドアを開けた途端に、冷たい風が部屋に入ってきた。
As soon as the staff member opened the door, a cold wind came into the room.
Example sentences
玄関のドアを開けた途端に、強い風が吹き込んできた。
Just as I opened the front door, a strong wind blew in.
電車が駅に着いた途端に、大勢の乗客が降り始めた。
As soon as the train arrived at the station, a large number of passengers began to get off.