Japan Airlines has an attractive deal for passengers booking flights to or through Japan on its flights: a free domestic flight within Japan to enjoy another city or region.
It’s not exactly free for all: passengers from U.S., Canada, Mexico and China who have had a ‘stopover’ fee for a Japan stopover longer than 24 hours will still have to pay that.
There’s a starter list of eligible countries, to be expanded later. The free flight must be booked at the same time as the international flight.