ては【～ては】

The particle combination ては (often contracted to ちゃ in casual speech) is used to express that if a certain action or state occurs, an undesirable result will follow. It carries a strong sense of warning, prohibition, or negative consequence.

Expressing undesirable conditions ("if … then [something bad]")

The most common use of ては is to state that doing something will lead to a negative outcome. It is frequently paired with negative expressions like いけない, だめ, こまる困る, or ならない.

In these patterns, ては literally means "if you do ~" and the following phrase states the negative consequence, creating the overall meaning of prohibition or strong advice against something.

Expressing natural negative consequences

Beyond explicit prohibition, ては can express that if something happens, a bad situation naturally results – often used to explain why something is problematic.

Here, the speaker is not giving a command but stating a cause-and-effect relationship where the condition leads to an undesirable outcome.

Repeated actions: ～ては～ては / ～ては～

ては can also express repeated or alternating actions, often conveying a sense of frustration, monotony, or persistence.

Casual contraction: ちゃ / じゃ

In informal speech, ては contracts to ちゃ, and では contracts to じゃ.

Related forms

• ～てはいけない / ～てはならない / ～てはだめ: Fixed prohibition patterns meaning "must not."
• ～ては～: Repeated-action pattern.
• Compare with ～たら and ～と, which also express conditional meaning but without the inherent negative nuance of ては.