Japanese food prices are ridiculously cheap. Well that's true to pretty much whole Asia too. Even in HK which I consider more expensive than Japan a Big Mac is only 2.9€ (27 HKD). And that's McD, local food spots are even cheaper. If you have the money there is no better time to have a holiday in Asia.

A Big Mac is 10€ in France...

We are ripped off big time in the US and Europe for nothing.

My guess about how/why McDonald's is so cheap in Hongkong: (1) Guangdong province is just north which means there are lot of farms with very cheap labor. (2) Minimum wage in Hongkong is frightening low. As a counterpoint, I would offer that retail/commercial real estate is crazy expensive. I have no idea how this translates into my McD's is so damn cheap in HK!

american fast food learned that if they try to hit the business market they can sell higher mark up items. it's why mcdonalds for a long time went to premium chicken and premium burgers that were more expensive. they changed strats, but for a while in the US that's what a lot of fast food was doing. they were chasing whales.