The installment plan, used for [card installments in Japan](https://docs.adyen.com/payment-methods/cards/credit-card-installments#make-a-payment-japan). By default, this is set to **regular**. Possibl
value
integer
Defines the number of installments. Its value needs to be greater than zero. Usually, the maximum allowed number of installments is capped. For example, it may not be possible to split a payment in mo