〜ておく — Japanese Grammar

〜ておく

Property	Value
Pattern	〜ておく
JLPT Level	N4
Type	preparation
Formality	Neutral
Register	Both

Meaning

The pattern 〜ておく (te-oku) is used to indicate that an action is performed in advance, as a preparation for a future event or to maintain a state for later use. It implies foresight and planning.

Structure Formula

[Verb te-form] + おく

• Conjugation: Take the te-form of any verb and attach おく (oku).
• Polite form: In polite speech, use 〜ておきます (te-okimasu).
• Casual/Spoken: In rapid, casual speech, 〜ておく often contracts to 〜とく (toku).

Detailed Explanation

The core meaning of 〜ておく is "to do something in preparation." It suggests that the speaker is taking a proactive step to ensure things go smoothly later, or to prevent a problem from occurring. It is the grammatical equivalent of saying "do [verb] in advance" or "get [verb] ready."

This pattern is highly versatile and used in both daily life and professional settings. Whether you are booking a hotel, buying ingredients for a meal, or saving a file on your computer, 〜ておく highlights the intentionality behind the action.

In spoken Japanese, especially among friends, the "e" sound is often dropped, turning 〜ておく into 〜とく. For example, shite oku (to do in advance) becomes shitoku. While this is very common in conversation, avoid using the contracted form in formal writing or business emails.

It is important to note that 〜ておく focuses on the preparation itself. If you want to emphasize that the state resulting from the preparation is being maintained, you might use 〜てある instead.

Example Sentences

Japanese	Reading	Romaji	English
明日のために、準備をしておく。	明日(あした)のために、準備(じゅんび)をしておく。	Ashita no tame ni, junbi o shite oku.	I will prepare for tomorrow in advance.
ホテルの予約をしておきました。	ホテルの予約(よやく)をしておきました。	Hoteru no yoyaku o shite okimashita.	I have made the hotel reservation in advance.
忘れないように、メモをしておく。	忘(わす)れないように、メモをしておく。	Wasurenai yō ni, memo o shite oku.	I'll make a note so I don't forget.
飲み物を冷やしておこう。	飲(の)み物(もの)を冷(ひ)やしておこう。	Nomimono o hiyashite okō.	Let's get the drinks chilled (in advance).
彼は会議の資料をコピーしておいた。	彼(かれ)は会議(かいぎ)の資料(しりょう)をコピーしておいた。	Kare wa kaigi no shiryō o kopī shite oita.	He copied the meeting materials in advance.
窓を開けておいてください。	窓(まど)を開(あ)けておいてください。	Mado o akete oite kudasai.	Please leave the window open (for now/for later).
晩ご飯を作っておくね。	晩(ばん)ご飯(はん)を作(つく)っておくね。	Bangohan o tsukutte oku ne.	I'll make dinner ahead of time, okay?
傘を持っていくといいよ。	傘(かさ)を持(も)っていくといいよ。	Kasa o motte iku to ii yo.	You should take an umbrella (in case it rains).

Comparison with Similar Patterns

〜ておく vs 〜てある

• 〜ておく emphasizes the action of preparing.
• 〜てある emphasizes the state of something having been done and remaining that way.

Pattern	Nuance	Example
〜ておく	Intentional preparation	窓を開けておく (I'll open the window [for ventilation later])
〜てある	Resulting state	窓が開けてある (The window is [already] open)

〜ておく vs 〜てみる

• 〜ておく is about preparation.
• 〜てみる is about trying something out to see what happens.

Common Mistakes

1. ❌ 宿題をやっておくつもりです。 (Technically correct, but redundant if the preparation is obvious.) ✓ 宿題をやっておきます。 (More natural for stating a plan.)
2. ❌ 準備をしてある。 (When you mean you will prepare it.) ✓ 準備をしておく。 (Use te-oku for the act of preparing.)
3. ❌ 窓を開けてあるください。 ✓ 窓を開けておいてください。 (Use te-oku for requests involving preparation.)

Practice Exercises

Fill in the blank (use 〜ておく or the correct form):

1. 旅行の前に、チケットを____。 (Buy the ticket in advance before the trip.)
2. 友達が来るから、部屋を____。 (I'll clean the room because a friend is coming.)
3. 忘れないように、カレンダーに____。 (I'll write it on the calendar so I don't forget.)
4. 冷蔵庫にビールを____。 (I'll put the beer in the fridge [to chill it].)
5. 明日の会議のために、資料を____。 (I'll read the materials for tomorrow's meeting.)

Answer Key:

1. 買っておく (katte oku)
2. 掃除しておく (sōji shite oku)
3. 書いておく (kaite oku)
4. 入れておく (irete oku)
5. 読んでおく (yonde oku)

JLPT Level Notes

In the JLPT N4, this pattern often appears in listening sections (where you must identify the speaker's intent) or in grammar multiple-choice questions. Look for keywords like 「ために」 (for the sake of) or 「忘れないように」 (so as not to forget), as these are strong indicators that 〜ておく is the correct choice. Remember that the contracted form 〜とく is common in listening, so be prepared to hear it!