Ask when something happens (いつ)
いつ asks “when” an event takes place. Unlike specific clock times, いつ is an open temporal adverb that never takes the particle に.
Asking When (いつ)
tanjoubi wa itsu desu ka
When is your birthday?
Open Time (いつ, No に) vs Specific Clock Time (何時に, With に)
Micro-Shiftいつ日本へ行きますか。
When are you going to Japan?
いつ is an open temporal adverb and never accepts particle に.
Example Sentences
When is your birthday?
When are you going to Japan?
The Open Timeline Mental Model
In Japanese, specific points on a calendar or clock (such as 三時に (at 3:00) or 五月五日に (on May 5th)) require the pin-point particle に.
However, いつ (when) represents an open, unpinned window in time. Because it is inherently adverbial, it drops directly into the sentence without any particle at all:
• 日本へいつ来ましたか: “When did you come to Japan?”
• Saying *いつに来ましたか is ungrammatical!
Flexible Sentence Position
Like most Japanese question words, いつ does not trigger English-style subject-auxiliary inversion. It simply replaces the time phrase:
- Statement: 来週、京都へ行きます (“I will go to Kyoto next week”).
- Question: いつ、京都へ行きますか (“When will you go to Kyoto?”).
- Topic first: 誕生日はいつですか (“When is your birthday?”).
High-Frequency Combinations
1. Source & Destination (から / まで): - いつからですか: “From when does it start / since when?” - いつまでですか: “Until when / what is the deadline?” 2. Indefinite Forms: - いつか: “Someday / at some point” (いつか日本へ行きたい = “I want to go to Japan someday”). - いつでも: “Anytime / whenever” (いつでもどうぞ = “Anytime you like!”). - いつの間にか (itsu no ma ni ka): “Before one realizes / unnoticed.”
In Dialogue
Maru日本語のテストはいつですか。
When is the Japanese test?
Hana来週の金曜日ですよ。一緒に勉強しましょう！
It's next week on Friday. Let's study together!
Build the Sentence
JLPT N5what is this?
Arrange the words in the correct Japanese order:
- Empty slot
- Empty slot
- Empty slot
- Empty slot
- what it's about · said "wa"
- this
- is it? (question)
- what