Common mistake: “WHEN” in Japanese : いつ, とき , たら , と…

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“WHEN” in Japanese : いつ, とき , たら , と

One of the most common mistakes I see is how learners express “when”.
Majority of my students (even advanced students) make mistakes on this one.
I cannot blame them because it is indeed confusing!
And the textbook doesn’t explain too clear!
But read this guide, and you’ll master the Japanese “WHEN” ★


When you look “when” up in a dictionary, you get いつ (itsu).
Fine, いつ does mean “when”. But you must be careful!
いつ can only be used as a question.


ITSU nihon ni ki-masu ka
= When will you come to Japan?

itsu nihon-go wo benkyou shi-hajimeta no?
= When did you start learning Japanese?

A: 久しぶりー!遊ぼうよ!
B: 久しぶり!うん、いいね。明日は暇?
A: ごめん、明日はちょっと・・・
B: そっか。じゃあ、いつがいい?私はいつでも暇だよ(笑)

A: Hisashiburi~ asobOU yo
B: Hisashiburi! Un, ii ne. Ashita wa hima?
A: Gomen, ashita wa chotto…
B: Sokka. Jaa, ITSU ga ii? watashi wa itsu-demo hima da yo

A: Long time no see! We should hang out! (lit. Let’s hang out!)
B: Long time no see! Yeah, cool! Are you free tomorrow?
A: Sorry, not tomorrow…
B: Alright. Then when is good for you? I’m always free lol

natsu-yasumi wa ITSU kara ITSU made desu ka
= From when to when is the summer holiday? (does it last)



Words that are created from “ITSU”.

いつ = someday

いつ = all the time / always

いつでも = (at) any time / whenever

いつから = from when

いつまで = until / to when




Then what do you use for a sentence like
When I was in Japan, I had lots of sushi.”?

Use とき / / toki !!
(The kanji means “time“.
Though as a word / noun “time”, we say ” 時間 (jikan)“)

When <sentence 1>, <sentence 2>

=  <sentence 1> とき, <sentence 2>

The first rule :
“<sentence 1 > とき” should come in the first place.
(Except : In informal speech, it can go at the end if you forget to put it first.)
The second rule :
DO NOT use  masu form or desu form. (i.e.  only put plain form) in the first clause.


Noun + とき
(toki is a noun, so remember? You always connect two different nouns with の particle!)

ame NO toki, yoku uchi de hon wo yomi-masu
= When it rains, I often read books at home.

juu-dai NO toki, oya to itsumo kenka shite-ita
= I was always arguing with my parents when I was a teenager.

kodomo NO toki, kumo ga kowa-katta desu
= When I was a child, I was scared of spiders.


As you can see from the examples above,
even when the tense in the second clause is present or past,
you don’t have to change anything before the とき.

However, you CAN make it past tense,
and it puts more emphasis on the fact that the action has taken place in the past.

And of course, to make a past tense, you need the help of a verb. (Here it is だった.)
So don’t put の.


gakusei datta toki, konbini de arubaito wo shite-ima-shita
= When I was a student, I used to do a part-time job in a convenience store. (konbini)

chichi ga mada pairotto datta toki wa, watashi wa san-sai deshita
= When my father was still a pilot, I was three years old.




And for negation, simply put じゃない or ではない (form.).


kankou shiizun ja nai toki ni* itta kara, hito ga suku-na-katta
= There weren’t many people because I went there in the off-season
(lit. when it was not the tourist season).


About, normally you don’t need to put に after とき.  But here’s when we often put it :

From “kankou” to “kara”, that’s the BIG actual “clause 1” and the rest is the “clause 2”.
But when you look at the “clause 1”, it’s made out of two parts :

観光シーズンじゃないときに  (kankou shiizun ja nai toki ni) + 行ったから (itta kara)
= When it wasn’t the tourist season + Because I went

Without に, it still works, but to make the sentence flow, it’s better to put に.


Also when you want to put emphasis on WHEN, に is often added.


A: いつ薬を飲めばいいですか。
itsu kusuri wo nom-eba ii desu ka
B: 痛いとき、飲んでください。
itai toki NI, nonde kudasai
= A: When should I take the medicine / pill?
B: Please take it when it’s painful.

*See, in this example, what B wants to say is mainly “WHEN to take”.
You’ll see more examples below.

Let’s move on to using adjectives!

As for adjectives, you don’t have to change or add anything.
For I-adjectives, い stays the same and for NA-adjectives, な stays the same too. Easy!


お母さんはケチだから、 寒いときでも、暖房をつけない。
okaasan wa kechi da-kara, samui toki demo* danbou wo tsuke-nai
= My mum is stingy so even when it’s cold, she doesn’t put heating on.

kyoushitsu ga shizuka-na toki, sensei wa ureshi-sou desu
= The teacher seems happy when the class is quiet.


Again, the past tense

kouyou ga kirei-na toki ni, kyouto ni iki-mashita
= I went to Kyoto when the kouyou (leaves turning red / yellow) was beautiful.

can be

kouyou ga kirei datta toki ni, kyouto ni iki-mashita

However, it can imply that there is no “Kouyou”
or it’s not beautiful anymore as it emphasizes that it was in the past.


So if the country used to be safe, but not anymore,
then you should use だった in the below example :

kono kuni ga (mada) anzen datta toki ni, umare-mashita
= I was born when this country was (still) safe.


So far, we’ve learnt that

the tense does NOT matter in nouns and adjectives!


Now this is the hardest part about using とき…


kono keeki wo tsukuru toki, itsumo reshipi wo mi-masu
= I always look at the recipe when I make this cake.

This one must be easy. Nothing weird about it.
Next I’ll show you the one that confuses the learners.

First, understand that when using た, it’s the past tense meaning “LEFT”.

uchi wo deru
= to leave the house / will leave the house

uchi wo deTA
= left the house


Now let’s put them in this pesky とき.

uchi wo deru toki
= When leaving the house
/ BEFORE actually leaving the house, but on the way

uchi wo deTA toki
= When I (actually, physically) left the house


That’s right,
the meaning changes depending on whether it’s present or past tense.
Let’s see them in an example sentence.

uchi wo deRU toki, denki wo keshita
= I turned the lights off when I was leaving the house.
(BEFORE leaving the house)

Here, you need to use でる (present) to show that you were still in the house
because you wouldn’t be able to turn the lights off outside of the house
unless you have a remote control or something.


uchi wo deTA toki, kagi wo kaketa
= I locked the door when I left the house.
(AFTER leaving the house)

Here, if you use the present tense,
it’d mean that you lock yourself in when you actually want to leave. Madness!



More examples :

Present tense “iku (= to go)” :

nihon ni iku toki, omiyage wo katta
= I bought souvenirs when I was on my way to Japan.
(was heading / going to Japan)

*The speaker maybe bought it at the airport in his own country,
for his friends / host family in Japan.
Past tense “itta (= went)” :

nihon ni itta toki, omiyage wo katta
= I bought souvenirs when I went to Japan.
(arrived there and bought it when I was there.)

*In this one, the speaker probably bought the souvenirs
for himself or his friends / family in his country.


heya ni hairu toki, nokku shite-kudasai
= Please knock on the door when entering the room.
(Before entering the room)

kuruma no doa-nobu wo sawatta toki-ni, bachi tto suru no wa seidenki no sei desu
= The “bzzt” feeling you get when (after) touching  the car door handle
is caused by static electricity.


michi wo wataru toki, mazu migi to hidari wo kakunin shite-kudasai
= Please check the right and left first when crossing
(before actually crossing) the road.


hannin ga michi wo watatta toki, mi-ushinatte-shimatta
= I lost sight of the criminal when (after) he crossed the road.



Although “past tense + とき” can express that the action was already done,
when you want to emphasize “AFTER” and “BEFORE”, use the different words.

For “Before“, use
Plain verb (not past) + まえ(に)


nihon ni iku mae-ni, omiyage wo katte-oita*
= I bought souvenirs before going to Japan.

* TE form + おく = to do ~ in advance

ban-gohan wo taberu mae-ni, te wo aratta
= I washed my hands before eating dinner.


For “After“, use
Plain past (た) あと(で*)
*で is often omitted

or   てform + から… = do (te form), then do ….
* This is used more commonly if you list the sequence of actions.


“kore ga ii” to omotta doresu wo mitsuketa kedo,
nedan wo mita ato (de), kau ki ga naku-natta

= I found a dress that made me think “I want this one!”
but after seeing the price, I lost my interest in buying it.

*Here you can use 見たとき instead of 見たあと.


uchi wo dete kara, denki wo kesa-nakatta koto ni kizuita
= I realized that I didn’t turn the lights off after leaving the house.


nihon ni tsuite kara, hoteru wo sagasu no wa ii kangae ja nai
= It’s not a good idea to look for a hotel after arriving in Japan.



The examples below are a little bit more complicated but worth knowing.

~とき noun …

kore wa fuji-san wo nobotta toki NO shashin desu
= This is the picture (lit. of) when I climbed Mt. Fuji.


nihon-go ga heta datta toki NO jibun no nikki wo mite, waratta
= I saw my diary from the time I was terrible at Japanese and laughed.
(lit. I saw the diary of myself of when I was terrible at Japanese and laughed.)



~ときから  = From / Since when

hajimete atta toki KARA, suki deshita
= I’ve always liked you since when I first saw / met you.
~ときまで =  Until when

amerika ni kaette-kita toki made, mainichi nihon-go de hanashite-ita
= I was speaking Japanese everyday until when I came back to the US.



= For (the sake of) when ~ / In case of ~

jishin ga okita toki no tame-ni, mizu wo takusan katte-oita
= I bought lots of water in case of the earthquake. (lit. for the time the earthquake happens)



ryokou ni iku toki ni hitsuyou-na suutsukeesu wo katta
= I bought a suitcase that is necessary when traveling.


denwa shita toki-ni  issho-ni ita hito wa dare
= Who was the person with you when I called you?



And this is what separates the intermediate from advanced students :

Using たら and と as “when” – 

If you’ve already learnt conditional “IF form” in Japanese, you probably know these.
If not, they can be translated as “IF” and “WHEN”.

First I’ll explain how to use the conditional “と”.
と as you may know means “and” if it’s between two nouns.
So technically <verb + と> cannot mean “verb + and”.
Because you’d have to use TE form instead.

Anyways,   is used for natural consequence.
Which means,
“when you do 1, 2 ALWAYS happens”.
present plain verb + と 、 sentence 2  = when / if …, sentence 2


For example, if you want to make the sentence
When you close your eyes, you cannot see anything.”
We can say this logic is always right.
…unless you are a chou-nouryoku-sha (psychic). (゚д゚)!


A lot of beginners would translate this using とき :
me wo tojiru toki, nani-mo mie-masen
Humm, sure, it’s まあまあ (okay / so-so).
But don’t you want to sound native? YES, now then what shall we use?

と!!! (^◇^)

me wo tojiru TO, nani-mo mie-masen
= When you close your eyes, you cannot see anything.


More examples :
When you press this switch, the lights go off.”

Unless it’s broken, this should also be something that always happens.

So let’s use と.

kono suicchi wo osu TO, denki wa kie-masu



When you put mentos in coke, the coke bursts out!”

メントスガイザー!!(mentos geyser!!)
Again it always happens. We can say it’s a natural consequence as well. So…

koora ni mentosu wo ireru to, koora ga fuki-dasu



When the meal is tasty, I feel happy.”

“Feeling happy” also naturally occurs.
And the speaker probably always feels happy when the meal is good.
I don’t think (s)he would be like “Ah, yesterday I was happy but today…nah.”.

is a bit odd so…

⇒ ごはんがおいしい、うれしくなる。
gohan ga oishii TO, ureshiku-naru


It’s been pretty good, right?
Now let’s move on!!


the simple past tense (た) + ら.  To make the simple past, learn TE form.

sentence 1 たら、 sentence 2

The main rule is :
the action in S1 has to happen before S2.
The sequence of “S1 ⇒ then S2” is the key in this one.
So when it does not follow “s1 ⇒ s2” logically or time-wise, you cannot use it.

So in a sentence like “When I did 1, 2 happened”, たら is used.
(Not like “I bought a car when I got a girlfriend.”.)


When I laughed, the tears came out.

warattara, namida ga deta


When I bought an umbrella in a rush, it stopped raining.

kasa wo isoide kattara, ame ga yanda


More examples using たら as when.

oya ga okottara, kodomo wa naki-dashite-shimatta
= When the parents told the child off  (got angry), he started crying.


ATM de okane wo dashitara, tesuuryou wo torareru
= When I take money out at the ATM, they take / charge a commission.


asa okitara, itsumo yoga wo shimasu
= I always do yoga when I get up.


chesu no yari-kata wo shira-nai to ittara, jeemuzu wa odoroita
= When I said that I don’t know how to play chess, James was surprised.


terebi wa tsuketara, totoro ga yatte-ita
= When I put the TV on, Totoro was on / playing.


heya ni modottara, denwa ga natte-ita
= When I came back to my room, the phone was ringing.



You can use たら instead of と.
It sounds more casual if you use たら when と can be used.


me wo tojitaRA, nani-mo mie-nai yo
= You cannot see anything when / if you close your eyes.


That’s it!
I hope you can now use “WHEN” in Japanese correctly :)
If you have any questions or thoughts, please leave a comment.
Sharing is caring x


Translator / Linguist / Japanese Teacher / Happy World Traveler/ manga, anime, comedy lover. Speaks Japanese, English, Russian and German.


  1. Thank you for the explanation! I always confuse using いつ and とき. Your explanation is very clear, it help me to learn Japanese ^^

  2. Sweet Jesus, it would have taken me ages to figure this out on my own! This is really helpful! Also, I like the colors :3

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  4. But how should one think of たら in a situation like this:


    In this role, ら just replaces が as “but”, and adds a feeling of surprise at the result. So it cannot be understood as “when”.

    1. This article was mainly about how to say “when” in Japanese so I didn’t cover everything about たら. Though たら can be translated as “when”, it’s best to think that たら almost like “THEN” or an arrow (→). “A たら B” is “A then B” or “A → B”. Also たら has the meaning of “discovering / finding out something”. I thought the exam would be difficult → (I found out that / I now know that) it was easy.

  5. Just stumbled upon your blog and it seems awesome! Looks like you have a lot of actual useful dialogue that can be used in real daily conversation. Kind of tired of coming across Japanese that seems totally useless and stiff.

    Anyway – if I wanted to ask someone “When are you free?” would it be…いつは暇?Or “When are you free again?” またいつは暇?


  6. This is really helpful! My textbook’s example of when to use とき totally didn’t make sense to me, so I’m glad I came across this. I tweeted it as well! :)

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