以来【いらい】

以来 (いらい) means "since" or "ever since" and is used to indicate that a state or action has continued from a specific point in the past up to the present. It emphasizes that something has been ongoing or unchanged since that time.

Basic usage

以来 attaches to nouns (often time expressions or events) and to the て-form of verbs.

Noun + 以来:

Verb[て] + 以来:

Key nuances

• 以来 strongly implies that the situation described in the main clause has continued without interruption from the starting point up to the present (or up to a reference point in the past). It is not used for one-time events that happened after a certain point.

• Because of this continuous nuance, 以来 often pairs with expressions like ずっと (the whole time) and ている (ongoing state).

  あのじけん事件いらい以来、ずっとふあん不安だ。

  Ever since that incident, I've been anxious the whole time.

• 以来 is used for events or time points that are relatively significant or memorable – not for trivial or very recent moments. For example, you would naturally say けっこん結婚いらい以来 (since getting married) but it would sound unnatural to say something like 「さっき以来」 (since a moment ago).

Comparison with ～てから

Both 以来 and 〜～てから can mean "since," but they differ in nuance:

• ～てから simply indicates sequence ("after doing X, Y happened") and does not require the result to be ongoing.
• 以来 emphasizes that the resulting state or action has continued since that point.

Formal usage

以来 is somewhat formal and is commonly found in written language, news, and formal speech. In casual conversation, 〜～てから or 〜～てからずっと is often preferred.