使役形

How it works

The causative (使役形) turns 'X does' into 'Y makes or lets X do'. The person who causes the action becomes the subject; the person who actually does it takes に when the verb has its own direct object, and を when it does not (a clause never carries two を). With an intransitive verb に is also possible when the sense is 'let' rather than 'make': 娘に行かせた.

1. Godan verbs: change the final う-row sound to the あ-row and add せる: 書く → 書かせる、読む → 読ませる、待つ → 待たせる、行く → 行かせる. Verbs ending in う take わ: 買う → 買わせる.
2. Ichidan verbs: drop る and add させる: 食べる → 食べさせる、見る → 見させる.
3. Irregular: する → させる、来る → 来させる（こさせる）.

The result is an ichidan verb, so it conjugates like any other: 書かせます、書かせない、書かせた、書かせて.

Two readings live in one form. Make (compulsion): 部長は私に報告書を書かせた. Let (permission): 子供を自由に遊ばせた. Adding ～てあげる／～てくれる tilts it toward permission (行かせてあげる = let someone go as a favor), and ～させてください asks for that permission.

Because the form asserts authority over the doer, it is natural for parents, teachers and bosses talking about people below them, and for talking about yourself. To describe a superior acting on your behalf, switch to ～てもらう／～ていただく.

Examples

• 母は子供に野菜を食べさせました。（はは は こども に やさい を たべさせました）— My mother made the children eat vegetables.
• 部長は私に報告書を書かせました。（ぶちょう は わたし に ほうこくしょ を かかせました）— The manager had me write the report.
• 子供を自由に遊ばせた。（こども を じゆう に あそばせた）— I let the kids play freely.
• 先生は学生に漢字を毎日書かせます。（せんせい は がくせい に かんじ を まいにち かかせます）— The teacher makes the students write kanji every day.
• 娘を一人で旅行に行かせるのは心配です。（むすめ を ひとり で りょこう に いかせる の は しんぱい です）— Letting my daughter travel alone worries me.
• 息子を留学させることにしました。（むすこ を りゅうがく させる こと に しました）— We decided to send our son to study abroad.

Compare with

• 受身形 (passive): 書かれる is 'be written'; 書かせる is 'make someone write'. Same base, opposite direction of control.
• ～てもらう: 友達に手伝ってもらった (a friend helped me, as a favor) vs 友達に手伝わせた (I made a friend help, by authority). The first is what you say about equals and superiors.
• ～させてください: the causative て-form + ください asks to be allowed to do something yourself: 帰らせてください.

Traps for Spanish, English and French speakers

• English 'make the children eat vegetables' treats the child as a direct object, so learners write ✗ 子供を野菜を食べさせた. With a transitive verb the person takes に (子供に野菜を食べさせた); を goes on the person only when the verb has no object of its own (子供を遊ばせた). Spanish and French already make this split (les hice comer verduras / je leur ai fait manger des légumes with a dative, los hice correr / je les ai fait courir with an accusative), so lean on it.
• English 'I had my hair cut' is not 髪を切らせた, which means you ordered or permitted someone to cut it. A service you receive is ～てもらう: 髪を切ってもらった.
• Spanish hacer and French faire are socially neutral, but させる asserts authority over the doer, so ✗ 先生に説明させます sounds like ordering your teacher around. Speak upward with ～てもらう／～ていただく: 先生に説明していただきます.
• Learners who memorize させる as 'the causative ending' attach it to godan verbs too: ✗ 読まさせる、✗ 行かさせる. Godan verbs take only せる (読ませる、行かせる); させる belongs to ichidan verbs, する and 来る.