Forms and Contexts of When in Japanese

In English the word when functions as a question word, a relative clause marker, and a conjunction expressing time. Japanese expresses these ideas with several distinct patterns, each with its own grammatical nuance. Below is an overview of the most common forms, the situations in which they appear, and example sentences to illustrate their use.

1. Temporal Question: (itsu)

is the basic interrogative for when. It is used in direct questions, polite requests, and indirect queries.

Direct questions

Polite form

Indirect question

2. Temporal Clause Markers

When when introduces a subordinate clause indicating the time of an action, Japanese uses several constructions. The choice influences formality, nuance, and whether the clause is completed before the main action.

2.1 ... (toki)

Attaches to verbs, adjectives, and nouns. It can refer to a specific moment or a broader period, depending on tense.

• Nonpast + the time before the main action occurs.
• Past + the time after the main action has occurred.

2.2 ... (tara)

Forms a conditional meaning when/if and is used when the speaker assumes the condition will be met.

2.3 ... (tekara)

Literally after doing , expresses a sequential relationship: the main action occurs after the subordinate action has been completed.

3. Relative Clause When

When when introduces a relative clause (e.g., the day when ), Japanese generally uses or after a noun.

4. When in Reported Speech

In indirect or reported questions, Japanese often replaces when with inside a clause introduced by verbs such as , , , etc.

5. Formal and Literary Alternatives

Some written or formal styles use older or more refined expressions.

• (itsu ni) at what time, common in formal writing.
• (itsu ka) sometime, often used in narrative prose.
• (jiki) period or time, used when referring to a broader timeframe.

6. Common Pitfalls

• Confusing with . Both can translate to when, but follows verbs/adjectives, while follows nouns.
• Mixing tenses incorrectly with . Remember: nonpast before the main verb, past after.
• Using for a simple temporal sense can add a if nuance; choose when the condition is certain.
• Overusing for simultaneous actions; it strictly means after doing .

7. Quick Reference Table

English when	Japanese form	Typical use
Question word		Direct/indirect questions
When (at the time that) (temporal clause)	/	Relative clause, temporal context
When (if) (conditional)	/ (nonpast)	Condition assumed to be met
After (sequence)		Action follows completed action
Formal at what time		Official documents, speeches
Indefinite sometime		Literary, narrative

Understanding which Japanese pattern to use depends on the grammatical role (question, subordinate clause, relative clause) and the temporal relationship you wish to convey. By recognizing the subtle differences among , , , and , you can express when accurately and naturally in a wide range of contexts.