But despite the fact that it's almost 20 degrees centigrade warmer in Osaka than in Berlin (and let's not even talk about Moscow), I've felt colder here than I ever did in my flat on Wühlischstrasse. That's because German houses have ultra-efficient, heavy duty heating systems, double glazing and insulation. Japanese houses don't. This came home to me most keenly in Hokkaido last year, where, despite kerosene and electric heaters and a denki kaapetto, I could never make my house so warm that I couldn't see my breath. I kept every single layer of clothes on when I was in the house; basically, it was like living outdoors. I even spent one particularly cold weekend camped up in the tiny bathroom, the only place I could conserve heat. For two days I sat on the toilet eating bento dinners, sipping beer from the coin machine across the road, and watching downloaded episodes of Nathan Barley. The kerosene heater turned the place into a sauna, and I kept the bath-tub full of hot water.
I expected the hacking cough I often get in winter to be much worse after two months in that Hokkaido house, but to my surprise it disappeared completely. Apparently living in those conditions was good for me. It certainly doesn't prevent the Japanese from living longer than anyone else in the world. And in the recent cold snap in north Japan, when almost a hundred people died, it was invariably because they fell off their roofs while attempting to clear them of snow, or were buried by collapsing snow-heavy roofs while they slept. These were not hypothermia deaths, deaths due to the cold itself.
The big question (and I've been asking everyone I meet the same thing) is, why is a nation capable of building the world's most advanced and comfortable technology not capable of heating its houses? "When I first came to Japan three years ago, I thought the Japanese were the stupidest people in the world," says Mint Woo, a Korean ad executive quoted in Bill Stonehill's interesting article The Cold and the Kotatsu. Koreans (partly because Korea is much colder than Japan) heat their houses the way the Chinese do; "when a building is being built, hot water pipes are laid in the cement floors of all the rooms. In winter, hot water is piped through them, making a very warm floor."
After talking with lots of people, I've collected a list of reasons why Japanese houses are so cold. None of these reasons is in and of itself sufficient, but together they add up to some sort of explanation.
Japanese houses are built for summer because, thanks to the warming Pacific current, the Japanese winter is short and mostly mild. Also, Japanese have a range of "localised heat" technologies which they (like us canny, mean Scots) prefer to the global heating systems of the West: the kotatsu table, the electric carpet, the heated toilet seat, even hot stick-on patches fuelled by chemical reaction, these provide spots of heat where and when you most need them. Apart from those, the omnipresent air conditioning unit serves as a (rather feeble) heater too. Also, the Japanese spend a lot of time out and about in public. In the public bath-house or the izakaya you can keep warm in company. What's more, the threat of earthquakes makes the Japanese build rather flimsy, throw-away houses.
But my favourite explanation is a religious-aesthetic one: the Japanese are extremely attuned to the seasons, thanks to their ancient agrarian national religion of Shinto. When it's winter, you should know it's winter. Don't walk around in a T-shirt pretending it's summer; it should feel cold. No wonder they go so crazy with joy when the first blossom arrives.