AirAsia are running a promotion on flights from Nagoya to Sapporo, Japan for only $2 USD one-way (or fly roundtrip for only $5 USD).
Also works in reverse.
Promotion ends 22nd October 2017.
Availability from October 2017 to March 2018
The AirAsia website conveniently allows you to view prices for each week so there is no need for a list of example dates from us.