Road traffic in Japan is a complicated affair. Apart from those narrow, crooked streets that sometimes end without warning, you have to get used to unclear right-of-way rules and the national fetish for backward parking. On top of that they drive on the wrong side of the road (though admittedly views may differ on that).
What can really give you the blues, however, is what they call their green traffic lights. Whereas 赤 (あか, red) and 黄 (き, yellow) basically go by the same name as everywhere else, the Japanese green light is not called 緑 (みどり), the Japanese word for green, but 青 (あお, blue).
To be sure about one thing, though some traffic lights in Japan may in fact look just a little bluer than elsewhere — we'll come to that in a minute — all of them are clearly within the physical spectrum defined as green. That's because the colors of traffic lights are subject to an international convention according to which the "go" signal must be green. No exceptions granted.