When you open a Japanese Booster Pack, there will be a coupon that usually says [残念].
But if you're lucky, the coupon will look this instead:
On the left is a Silver Trigger, while on the right is a Gold Trigger.
A Silver Trigger is worth 1 point, while a Gold Trigger is worth 3 points.
These coupons can be exchanged for various Bushiroad merchandises.