～（さ）せる
make or let someone do
The causative form means that the subject causes someone else to act, either by making them (“made him go”) or by letting them (“let her go”). Japanese uses one form for both, and context tells you which.
The person who is made or allowed to act is marked with に, or with を when the verb is intransitive (has no object of its own).
1. Making someone do something
With a transitive verb, the person being made to act takes に and the thing acted on keeps its を.
母は子供に野菜を食べさせた。
“The mother made the child eat vegetables.”
- 母（はは）= mother
- は = topic marker
- 子供（こども）= child
- に = marks the person made to act
- 野菜（やさい）= vegetables
- を = object marker
- 食べさせた（たべさせた）= made (them) eat
2. Letting or allowing
The same form means giving permission. In て-form requests it asks for permission for yourself: 行かせてください = “please let me go”.
子供を公園で遊ばせる。
“I let the children play in the park.”
- 子供（こども）= children
- を = marks the person allowed to act (intransitive verb)
- 公園（こうえん）= park
- で = location marker (in/at)
- 遊ばせる（あそばせる）= let (them) play
How to form it
Godan (u-) verbs: change the final u-sound to its a-row sound and add せる. Ichidan (ru-) verbs: drop る and add させる. Irregular verbs: する → させる, 来る → 来させる（こさせる）.
- 行く（いく）= to go → 行かせる（いかせる）= make/let go
- 飲む（のむ）= to drink → 飲ませる（のませる）= make/let drink
- 食べる（たべる）= to eat → 食べさせる（たべさせる）= make/let eat
- する = to do → させる = make/let do
- 来る（くる）= to come → 来させる（こさせる）= make/let come
Key idea
～（さ）せる means the subject holds the power. Whether that power is used to force or to permit is decided by context.
Built on the same stem
Updated .