Japanese causative and causative-passive

Forming the causative

The causative says that someone makes or lets another person do something. Ru-verbs replace る with ～させる (-saseru): (taberu) → (tabesaseru). U-verbs change their last sound to the a row and add ～せる (-seru); a final う becomes わ: (kau) → (kawaseru). (suru) becomes (saseru) and (kuru) becomes (kosaseru).

All causative forms are ru-verbs: (tabesaseta), (tabesasete), (tabesasemasen).

Verb	Causative	Polite
(taberu), eat	(tabesaseru)	(tabesasemasu)
(yasumu), rest	(yasumaseru)	(yasumasemasu)
(iku), go	(ikaseru)	(ikasemasu)
(matsu), wait	(mataseru)	(matasemasu)
(iu), say	(iwaseru)	(iwasemasu)
(suru), do	(saseru)	(sasemasu)
(kuru), come	(kosaseru)	(kosasemasu)

Make or let

The same form means both “make” and “let”; the situation tells you which. (tsuma wa watashi ni yasai o tabesasemasu) is “my wife makes me eat vegetables”; (musume ni suki na fuku o erabaseru) is “I let my daughter choose the clothes she likes”.

The person who does the action takes (ni) when the verb already has an object with (o). With verbs that have no object, the person usually takes : (kodomo o kōen de asobaseru), I let the children play in the park. A very common use is (omatase shimashita), sorry to have kept you waiting.

医者は父にたばこをやめさせました。Isha wa chichi ni tabako o yamesasemashita.The doctor made my father give up smoking.
雨だったので、子供たちを家の中で遊ばせた。Ame datta node, kodomotachi o ie no naka de asobaseta.It was raining, so I let the children play indoors.
心配させてごめんね。Shinpai sasete gomen ne.Sorry I made you worry.

Let me: ～させてください

The te-form of the causative + (kudasai) asks for permission to do something yourself: “please let me”. It's the natural way to offer to pay, to ask for time or to ask for a day off: (sukoshi kangaesasete kudasai), let me think about it a little.

ここは私に払わせてください。Koko wa watashi ni harawasete kudasai.Please, let me pay for this.
すみません、明日は休ませてください。Sumimasen, ashita wa yasumasete kudasai.Excuse me, may I take tomorrow off?

～させていただく

～させていただく (-sasete itadaku), literally “humbly receive permission to do”, is a very polite way to talk about your own actions, especially in business and formal speeches: (honjitsu no shikai o tsutomesasete itadakimasu), I will be your host today. The less formal ～させてもらう (-sasete morau) means “I was allowed to”, with gratitude.

In modern Japanese ～させていただく is often overused, even when no one's permission is needed. It fits best when you really are acting with the listener's permission or for their benefit; elsewhere, a humble verb or simple ～ます is enough. Note that u-verbs take ～せていただく: (yomasete itadakimashita).

お先に失礼させていただきます。Osaki ni shitsurei sasete itadakimasu.If you'll excuse me, I'll leave before you.
では、始めさせていただきます。De wa, hajimesasete itadakimasu.Well then, I'll begin.
若いころ、師匠の仕事を手伝わせてもらいました。Wakai koro, shishō no shigoto o tetsudawasete moraimashita.When I was young, my master let me help with his work.

Being made to: the causative-passive (B2)

The causative-passive says that you were made to do something against your will. Put the causative into the passive: ～させる → ～させられる (-saserareru). (tabesaserareru), to be made to eat; (saserareru), to be made to do.

For u-verbs, the full form is a row + ～せられる (, mataserareru), but in speech the short form a row + ～される is much more common: (matasareru), to be kept waiting; (nomasareru), to be made to drink. Verbs ending in す only have the long form: (hanasaserareru).

Verb	Causative	Causative-passive
(taberu), eat	(tabesaseru)	(tabesaserareru)
(matsu), wait	(mataseru)	(matasareru)
(nomu), drink	(nomaseru)	(nomasareru)
(hanasu), speak	(hanasaseru)	(hanasaserareru)
(suru), do	(saseru)	(saserareru)
(kuru), come	(kosaseru)	(kosaserareru)

昨日も遅くまで残業させられた。Kinō mo osoku made zangyō saserareta.I was made to work late again yesterday.
病院で一時間も待たされました。Byōin de ichijikan mo matasaremashita.I was kept waiting at the hospital for a whole hour.
子供のころ、ピアノを習わされた。Kodomo no koro, piano o narawasareta.As a child, I was made to take piano lessons.