I have a couple of theories for the small size of Japanese windows. They could be to increase the insulation efficiency of the house. Perhaps Japanese fear the windows shattering in earthquakes or typhoons. Even if those were the reasons, though, they could easily be compensated for. First off, Japanese houses have poor insulation, and inefficient heating systems. The best winter-system that I’ve experienced was in Korea, where houses have a boiler-system that heats the floor. But even standard central-heating would be better than a kotatsu or space-heater.As for the windows - Tempered glass, thicker panes.Another common feature in Japanese homes is the fluorescent lighting system. I can’t stand fluorescent lights. But most Japanese complain of “dark rooms”. Well, what do you expect when you’ve got windows the size of an encyclopedia?Any wall-space not surrounding the supporting pillars could be converted into windows. I want windows that span most of the open space on my walls. If you’re concerned about insulation in extreme weather, window companies could produce removable inserts to prop in front of the windows when needed. You’d be producing better living-spaces and creating jobs in a new sub-market!Check out the house below; a pretty standard house around my neighborhood."