～ておく

RuleVerb te-form + oku: doing something in advance or in preparation ("do beforehand").

Curiosity

How do you express doing something in advance, as in "I buy the tickets beforehand for the trip"?

Intuition

oku ("to place") adds the sense of "do it and leave it ready." It carries a nuance of preparing now so things go smoothly later. In speech it often shortens to ~toku (kattoku).

Visualization

kau (buy) → katte (te-form) → katte oku (buy in advance). oku on the te-form marks preparation.

買うdictionary (buy)

Essence

Verb te-form + oku (katte oku, yoyaku shite oku). Two senses: (1) advance preparation ("do beforehand"); (2) leaving as is ("let it stay"). Close to the resultant te-aru, but te-oku focuses on the act/preparation while te-aru focuses on the remaining state.

Examples

旅行の前に切符を買っておきます。

I will buy the tickets before the trip.

ビールを冷やしておきました。

I chilled the beer in advance.

会議の資料を準備しておいてください。

Please prepare the meeting materials in advance.

Mini-quiz

Which fits "I clean up in advance before the guests come"?