My birthday is coming up, and I'll probably be back in Japan a little bit after that time. Which reminded me:
For those who aren't aware, JAL offers a MASSIVE discount on all domestic flights if you fly on (or around) your birthday. I used this to get from Osaka to Hokkaido on the cheap last year.
Here's the flight I'll be taking this year, as an example of prices. From Osaka to Ishigaki (south of Okinawa):
Normal price (one-way): ¥45,400 (US $400)
Birthday discount (one-way): ¥13,300 (US $110)
So I save $600 round trip.
For those who haven't flown JAL, it is a very pleasant experience. They give you free soup & drinks. And they knew there would be two foreigners on our flight, so they made sure two English newspapers were available for us. And they gave us the emergency exit row seats both ways, without me even having to ask. (I assumed that this was because they thought that foreigners, being taller, need more leg room.) It's no Air Singapore, but they make for a damn pleasant flight.
Any travel agent in Japan can arrange this for you, or you can book the flight on the JAL website.