In the check-out pop-up that appears after selecting the film to rent, click on the 'I have a promo code' box before continuing with your transaction.
Enter your membership code in the promo code box that appears under the checkbox and then click 'Apply'. If you are not sure where to access your promo code, please check your email for discount codes from the Japan Society Membership Department. If you are a new member, the discount code is included in the emailed receipt for your membership. Please email email@example.com if you are unable to find the discount code.
Once the promo code is applied, the discounted rate should appear in the checkout window. Enter your credit card details and then click 'Rent' - you should be all set!