>> .. Airpass system. If you arrive and depart Japan on a carrier associated with one of the airline alliances like Oneworld you can purchase coupons for a substantial discount.
No need to be flying with any alliance to qualify for other foreign-tourist-only discounted air tickets, same price (or even cheaper) on ANA or JAL, and Air Do. Bookable online only.
On the other hand "Airpass" must be booked through a travel agent or the airlines, and some charge as much as 50 USD extra for the privilege.