せる・させる (Causative)To make/let/have (somebody do something)

In order to express that someone was 'made to do', or 'let do' something, the auxiliary verbs せる and させる will be used. The meaning that せる and させる will convey (when attached to a verb) is called 使役(しえき) (causative, employment, or using) in Japanese.

A common misconception is that せる and させる are standard conjugations of each verb. However, these auxiliary verbs should be thought of as having their own meaning, in a similar way to how たい, ない, だ, です, and other auxiliaries each have their own meanings.

In order to use these grammar structures, remove the る from る-Verbs, and then add させる. For う-Verbs, change the last kana to the あ sound kana from within the same column (except for う, which becomes わ), and then add せる (る becomes ら, む becomes ま, く becomes か, etc.).

As usual, する and 来(く)る have special conjugation rules. する will be replaced completely by させる (in a similar way to how できる completely replaces する in the 'potential' form). 来(く)る will become 来(こ)させる.

Caution

With causative, either に, or を can mark the doer of the action that せる, or させる is linked to (not が). This is because the actual 'doer' of the action is considered to be the person that is making/letting someone perform that action. に will usually imply that someone was 'let' do something, while を implies 'make'.

Fun Fact

Because the actual 'doer' in causative verb sentences will be marked with が (as is always the case), the literal translation of せる and させる is closer to the following:

(A) が (B) に楽しませる - For (A) to cause fun 'in' (B).

(A) が (B) を楽しませる - For (A) to cause fun 'through' (B).

It is these standard meanings of the particles に (a location) and を (a target) that will create the 'let', or 'make' nuance when using せる, or させる.