ておく【～ておく】

The grammar structure ～ておく expresses doing something in advance or in preparation for a future situation. It carries the nuance that the action is done deliberately now so that things will be ready or convenient later.

Doing something in preparation

The most common use of ～ておく is to describe actions done ahead of time to prepare for something.

The key nuance is intentionality – the speaker is consciously doing something now because it will be needed or useful later.

Leaving something in a certain state

～ておく can also mean to leave something as it is on purpose, either because changing it would be undesirable or because the current state is preferred.

Here, the focus is not on preparation but on intentionally maintaining a state.

Conjugation

Since おく is a godan (u-verb), it conjugates normally:

• Non-past polite: ～ておきます
• Past: ～ておいた
• Past polite: ～ておきました
• Negative: ～ておかない
• Volitional: ～ておこう

Shortened form: ～とく

In casual speech, ～ておく is often contracted to ～とく.

This contraction also applies to conjugated forms:

• ～ておいた → ～といた
• ～ておいて → ～といて
• ～ておきます → ～ときます