Saseru

Saseru, written in kana as させる, is the Japanese causative form used to indicate that the subject causes someone else to perform an action or allows someone to do so. It is a common grammatical tool in everyday Japanese, used with a range of verbs to describe making or permitting an activity.

Formation and patterns: For godan ( u-verb) verbs, the final u sound is changed to あせる or わせる depending on the verb, resulting in forms such as 行く → 行かせる, 話す → 話させる. For ichidan (る-verb) verbs, the final る is replaced with させる, as in 食べる → 食べさせる, 見る → 見させる. The special verbs する and 来る become させる and 来させる (kosaseru). The te-form of saseru is させて, used to connect clauses, and the causative passive form is させられる, meaning “to be made to do.”

Usage and meaning: Saseru expresses two primary meanings, depending on context: (1) causative meaning “to make someone do something,” where the subject compels the object to act; and (2) permissive meaning “to let someone do something,” where the agent allows the action. Context, tone, and particles help distinguish the sense. Common patterns include XはYにVさせる (X makes Y do V) and XはYをVさせる or XはYにVさせてあげる (X lets Y do V; adding あげる emphasizes giving permission or help).

Examples: 先生は学生にレポートを書かせる。 (The teacher makes the student write the report.) 母は子どもを公園で遊ばせる。 (The mother lets the child play in the park.) 私は友人にその本を読ませることができる。 (I can have my friend read that book.)

Related forms include the causative-passive させられる, used when the subject is made to do something.