The short version: とき means when and attaches like a noun: 行くとき, 寒いとき, 暇なとき, 子どものとき. The verb before とき does not show past or present. It shows order: the dictionary form means the event has not happened yet when the main action takes place, and the た-form means it already has. So 日本へ行くとき、かばんを買いました means you bought the bag before or on the way, and 日本へ行ったとき、かばんを買いました means you bought it in Japan.
Most learners first meet とき in a sentence like 暇なとき、何をしますか (What do you do in your free time?) and file it away as an easy word. The trouble starts when a verb comes before it, because English and Japanese use the tense of that verb for different jobs. In English, “when I went” is past simply because the story is in the past. In Japanese, the form tells the listener something more precise: had this event already happened at the moment of the main action?
How to attach とき
| Word type | Pattern | Example | Meaning |
|---|---|---|---|
| Verb, not yet done | dictionary form + とき | 行くとき | when (I am) going |
| Verb, already done | た-form + とき | 行ったとき | when (I had) gone, after arriving |
| Verb, in progress | ている + とき | 待っているとき | while (I was) waiting |
| Verb, negative | ない-form + とき | 分からないとき | when (you) don't understand |
| い-adjective | adjective + とき | 寒いとき | when it is cold |
| な-adjective | adjective + な + とき | 暇なとき | when (I am) free |
| Noun | noun + の + とき | 子どものとき | when (I was) a child |
In other words, とき behaves exactly like a noun such as 人 or 店: whatever describes it goes in front, in the same form you would use before any noun. You will see it written both as とき and as 時; grammar books usually write it in hiragana when it means “when”.
The famous pair: 行くとき vs 行ったとき
日本へ行くとき、かばんを買いました。
にほんへいくとき、かばんをかいました。I bought a bag for my trip to Japan.日本へ行ったとき、かばんを買いました。
にほんへいったとき、かばんをかいました。I bought a bag when I was in Japan.Both sentences end in 買いました, so both are about the past. The verb before とき answers a different question. With 行く, the trip was not yet complete when the bag was bought. With 行った, the trip was complete, so you were already in Japan.
The same logic in phrases you already know
Japanese daily greetings follow this rule exactly, which makes them a good way to remember it. Each one is tied to a moment either just before or just after an action.
帰るとき、コンビニで牛乳を買いました。かえるとき、コンビニでぎゅうにゅうをかいました。On my way home, I bought milk at a convenience store.
家に帰ったとき、だれもいませんでした。いえにかえったとき、だれもいませんでした。When I got home, nobody was there.
A future sentence with a past form, and the reverse
Because the form inside とき only shows order, it can disagree with the tense of the whole sentence. These two examples look strange to English speakers, and they are completely normal Japanese.
来年、日本へ行ったとき、友だちに会います。らいねん、にほんへいったとき、ともだちにあいます。When I go to Japan next year, I'll meet my friend.
昨日、家を出るとき、雨が降っていました。きのう、いえをでるとき、あめがふっていました。Yesterday, when I was leaving the house, it was raining.
While: ているとき
To say that something happened in the middle of another action, put the verb in the ている form before とき.
勉強しているとき、電話が鳴りました。べんきょうしているとき、でんわがなりました。While I was studying, the phone rang.
電車を待っているとき、先生に会いました。でんしゃをまっているとき、せんせいにあいました。I ran into my teacher while I was waiting for the train.
Adjectives and nouns: 暇なとき, 子どものとき
暇なとき、何をしますか。ひまなとき、なにをしますか。What do you do in your free time?
寒いときは、温かいお茶を飲みます。さむいときは、あたたかいおちゃをのみます。When it's cold, I drink hot tea.
子どものとき、よく川で遊びました。こどものとき、よくかわであそびました。When I was a child, I often played by the river.
とき, ときに or ときは?
All three are correct, and in many sentences the difference is small. As a rule of thumb:
ときに: at that moment
Points to the exact time something should happen.駅に着いたときに、電話してください。
えきについたときに、でんわしてください。Please call me when you get to the station.ときは: in that situation
States what you do whenever that situation arises, often as a habit or in contrast with other times.分からないときは、聞いてください。
わからないときは、きいてください。If there's anything you don't understand, please ask.Check yourself: before or after?
Ask: had the event already happened at the time of the main action?
国へ ＿＿ とき、空港でおみやげを買いました。くにへ ＿＿ とき、くうこうでおみやげをかいました。When I was flying home, I bought souvenirs at the airport.
You had not got home yet, so 帰る.
朝、＿＿ とき、「おはよう」と言います。あさ、＿＿ とき、「おはよう」といいます。When we wake up in the morning, we say good morning.
You say it after you are up: 起きた.
家を ＿＿ とき、「いってきます」と言います。いえを ＿＿ とき、「いってきます」といいます。When leaving home, we say ittekimasu.
You say it just before leaving, so the dictionary form 出る.
来年、大阪へ ＿＿ とき、たこ焼きを食べます。らいねん、おおさかへ ＿＿ とき、たこやきをたべます。When I go to Osaka next year, I'll eat takoyaki.
You will eat takoyaki in Osaka, after arriving: 行った, even though the sentence is about the future.
＿＿ とき、よく映画を見ます。＿＿ とき、よくえいがをみます。When I'm free, I often watch films.
暇 is a な-adjective, so it keeps な.
＿＿ とき、犬を飼っていました。＿＿ とき、いぬをかっていました。When I was a child, we had a dog.
Nouns take の before とき.
Quick reference
- Attaching とき
- Like a noun: 行くとき, 行ったとき, 待っているとき, 寒いとき, 暇なとき, 子どものとき.
- Dictionary form + とき
- The event has not happened yet at the time of the main action: 家を出るとき「いってきます」.
- た-form + とき
- The event has already happened: 家に帰ったとき「ただいま」.
- The famous pair
- 日本へ行くとき買った = bought before arriving. 日本へ行ったとき買った = bought in Japan.
- Mixed tenses are normal
- 来年日本へ行ったとき、友だちに会います. 昨日家を出るとき、雨が降っていました.
- While
- ている + とき: 勉強しているとき、電話が鳴りました.
- ときに / ときは
- ときに = at that moment. ときは = in that kind of situation.
Related Reading on Kanjijo
Frequently Asked Questions
行くとき means the going has not been completed when the main action happens: before leaving or on the way. 行ったとき means you had already arrived. 日本へ行くとき、かばんを買いました: you bought the bag for the trip. 日本へ行ったとき、かばんを買いました: you bought it in Japan.
No. It shows the order of events. The dictionary form means the event has not happened yet at the time of the main action, and the た-form means it has. That is why a future sentence can say 来年日本へ行ったとき、友だちに会います.
い-adjectives attach directly: 寒いとき. な-adjectives keep な: 暇なとき. Nouns take の: 子どものとき, 雨のとき.
子どものとき. The noun form is the normal way to say it, and the past tense of the main verb already places it in the past: 子どものとき、よく川で遊びました.
ときに points to the moment something happens: 駅に着いたときに、電話してください. ときは states what you do in that kind of situation, often as a habit or in contrast: 寒いときは、温かいお茶を飲みます.
- Seiichi Makino & Michio Tsutsui, A Dictionary of Basic Japanese Grammar (The Japan Times, 1986): entry for toki, including the relative tense of the clause before it.
- The Japan Foundation & JEES, JLPT Level Summary: what N4 candidates are expected to understand.
Hear とき in real conversations
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