いつ

When

Level 1Sounds Like itsu

いつ is the universal Japanese word for 'when'. It is used to ask about dates, times, or general periods without needing specific particles like に.

How It Works

1. Basic Usage
いつ functions as an interrogative word meaning 'when'. It usually appears before the verb or at the beginning of the sentence. Unlike specific time words, it does not take the time particle に. (Note: In the common phrase 「いつにしますか」, the に is NOT the time particle, but rather the particle for choice/decision used with the grammar pattern Noun + にする。)
Example: いつ行きますか。（When will you go?）
Example: いつ日本に来ましたか。（When did you come to Japan?）

2. いつ vs. 何時 (What time)
いつ asks for a general time (day, month, year, etc.), while 何時（なんじ） asks for a specific clock time. いつ is almost always written in hiragana because the kanji 何時 is usually read as なんじ.

3. Using with the Copula and Nouns
It can be used with です to ask when an event is (e.g., テストはいつですか). By adding の, it becomes a noun modifier (いつの) to ask 'from when' or 'which time's' (e.g., いつの写真ですか - 'From when is this photo?').

4. Combinations with Particles and Suffixes
いつ frequently combines with particles and suffixes:

  • いつが: When (as subject, e.g., いつがいいですか - 'When is good for you?')
  • いつから: From when / Since when
  • いつまで: Until when
  • いつまでに: By when (deadline)
  • いつごろ: About when

5. Indirect Questions
To say 'I don't know when...', use いつ with the question particle か inside the sentence.
Example: いつ行くか分かりません。（I don't know when I will go.）

6. Adverbs & Set Phrases
Adding particles creates new words: いつか (someday / sometime), いつも (always), いつでも (anytime), いつまでも (forever / indefinitely). A very common set phrase is いつの間にか (before I knew it / unnoticed). You will also frequently see いつもの (the usual, e.g., いつもの店 - the usual shop).

7. Distinction from 'When' as a Conjunction
In Japanese, いつ is an interrogative (question) word and cannot be used as a conjunction. To connect clauses (e.g., 'When I was a child...'), use 時（とき）.

Examples (6)

  1. 誕生日はいつですか。

    When is your birthday?

    Word by Word: Birthday (topic) when is it?

    A very common way to use いつ with the polite copula です.

  2. いつ日本に来ましたか。

    When did you come to Japan?

    Word by Word: When Japan to came (question)?

    Here, いつ is used as an adverb before the verb. Note that no particle follows いつ.

  3. 夏休みはいつからですか。

    From when is summer vacation?

    Word by Word: Summer vacation (topic) when from is it?

    Combining いつ with から (from) to ask for a starting point.

  4. 次の会議はいつごろ始まりますか。

    About when will the next meeting start?

    Word by Word: Next meeting (topic) when about starts (question)?

    Using いつごろ to ask for an approximate time rather than an exact one.

  5. これはいつの写真ですか。

    When is this photo from?

    Word by Word: This (topic) when's photo is it?

    Using の to make いつ a noun modifier, asking what time period the noun belongs to.

  6. いつ帰るか分かりません。

    I don't know when I will return.

    Word by Word: When return (question) don't know.

    An indirect question using いつ and the question particle か embedded inside a larger sentence.

Common Mistakes

  • Using the particle に after いつ.

    いつに行きますか。
    いつ行きますか。

    Relative time words like いつ、今日（きょう）、and 明日（あした） do not take the particle に. Only specific times like '3 o'clock' or 'Monday' do.

  • Using いつ as a conjunction meaning 'at the time that'.

    いつ子供でした、日本に住んでいました。
    子供の時、日本に住んでいました。

    いつ is used for questions (direct or indirect). To say 'When I was a child...', you must use the grammar pattern 時（とき）.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

いつLevel 1When

Learn This First

To use 'いつ' (when) effectively, you need to understand basic Japanese sentence structure and how to mark a sentence as a question using the particle 'か'.

Words in This Pattern