What is the Causative Form?
The causative form is how you express making someone do something or letting someone do something. "The teacher made the students read aloud." "Mom let me go to the party." Both causative territory.
It's one of those forms that trips people up at first because the conjugation is long, but the pattern is actually predictable. If you already know the ない form, you're halfway there -- the causative starts from the exact same あ-row base. Our lesson on passive and causative forms walks through real-world usage of both.
Conjugation Rules
U-verbs (Group I)
Change the final う-row sound to its あ-row equivalent, then add せる. For verbs ending in う, replace with わ + せる:
| Dictionary | Causative |
|---|---|
| 買う (kau) | 買わせる |
| 待つ (matsu) | 待たせる |
| 飲む (nomu) | 飲ませる |
| 泳ぐ (oyogu) | 泳がせる |
| 行く (iku) | 行かせる |
| 話す (hanasu) | 話させる |
The pattern: う→わせる, く→かせる, す→させる, つ→たせる, む→ませる, ぶ→ばせる, ぐ→がせる, る→らせる.
Ru-verbs (Group II)
Drop る, add させる:
| Dictionary | Causative |
|---|---|
| 食べる (taberu) | 食べさせる |
| 見る (miru) | 見させる |
| 覚える (oboeru) | 覚えさせる |
Irregular Verbs
| Dictionary | Causative |
|---|---|
| する | させる |
| 来る (kuru) | こさせる |
The に vs を Distinction
This is the part that really matters for meaning. The particle you use for the person being caused to act changes the nuance:
に = let / allow
- 子供に遊ばせる。
Let the kids play.
を = make / force
- 子供を走らせる。
Make the kids run.
When the verb is transitive (already takes を for its object), you use に for the person regardless, since you can't have two を in one clause:
- 生徒に本を読ませる。
Make/let the students read a book.
In this case, whether it's "make" or "let" depends on context and tone.
Causative Verbs Become Ru-verbs
Once you've made a verb causative, it acts like a ru-verb for all further conjugation. You can freely attach て form, ない, ます, and so on:
- 食べさせる → 食べさせます (polite)
- 行かせる → 行かせない (negative)
- 飲ませる → 飲ませて (te-form)
You can even stack causative with passive form to create the causative-passive -- "was made to do."
The Basic Pattern
Causer は Person に/を Action(causative)
- 母は私に野菜を食べさせた。
Mom made me eat vegetables. - 先生は生徒を立たせた。
The teacher made the students stand.
Example Sentences
-
好きにさせてよ。 (suki ni sasete yo.)
Let me do what I want. -
部長は私に残業させた。 (buchou wa watashi ni zangyou saseta.)
The boss made me work overtime. -
お客さんを待たせてすみません。 (okyakusan wo matasete sumimasen.)
Sorry for making you wait. -
子供に好きなものを選ばせた。 (kodomo ni suki na mono wo erabaseta.)
I let the kids choose what they liked. -
先生が生徒に作文を書かせた。 (sensei ga seito ni sakubun wo kakaseta.)
The teacher had the students write essays. -
ちょっと考えさせてください。 (chotto kangaesasete kudasai.)
Please let me think for a moment. -
彼はいつも人を笑わせる。 (kare wa itsumo hito wo warawaseru.)
He always makes people laugh. -
無理に食べさせないで。 (muri ni tabesasenaide.)
Don't force me to eat.