为什么中国只有一个时区？

English (for the teacher)

January in Kashgar, nine in the morning. The alarm goes off right on time, but outside it is still pitch dark: the streetlights are on, and a few stars still hang in the sky. At that same moment in Beijing, more than three thousand kilometres away, the sun has been up for over an hour. In Kashgar, you have to wait until after ten to see the first ray of sunlight. By the sun’s own clock, it is really only about six.

Nothing is wrong with Kashgar’s clocks. All of China runs on one time, Beijing time, which is UTC+8. Yet from west to east China stretches across more than sixty degrees of longitude, which by the usual international division would cover about five time zones.

Kashgar and Beijing sit at almost the same latitude, and their days are about the same length, yet Kashgar’s sun runs more than two and a half hours behind. Around the winter solstice, at three in the afternoon, the sun in Kashgar has only just reached its highest point, while in Fuyuan, Heilongjiang, at China’s eastern tip, it is already about to set. Go further southwest from Kashgar, to China’s border with Afghanistan, and the clocks on the two sides differ by a full three and a half hours.

In fact, China has not always lived by a single clock. In 1918, the Central Observatory of the day proposed dividing the country into five time zones: Changbai in the northeast, Zhongyuan for most of the east and centre, Longshu around Gansu and Sichuan, and Xinzang and Kunlun splitting Xinjiang and Tibet between them. The government later announced the plan officially, but in practice it was followed mainly along the coast. After 1949, one place after another switched to Beijing time, and the five zones on the map gradually became one.

But the sun does not change to suit the rules. In Xinjiang, many people still keep a second clock in their heads, called “Xinjiang time”, two hours behind Beijing time. In 1986 it even won official recognition, under the name “Ürümqi time”. So when you arrange to meet someone there, you often have to ask first: “Do you mean Beijing time or Xinjiang time?” And that is the simple version. From 1986 to 1991 the whole country also had daylight saving time, and in Xinjiang in those years, so the story goes, as many as four different times could be in use at once.

Luckily, trains and planes need no thought: they all run on Beijing time. As for daily routines, the whole day simply shifts later. Many workplaces open at ten in the morning, break for lunch at two and close at eight in the evening, and school hours are pushed back too. In summer, the sun in Kashgar does not set until about half past ten at night, and it is nearly eleven before it gets truly dark.

So is this a good idea? Supporters say one country, one clock is simple and a symbol of unity: train timetables and TV news need no converting, and more than ninety percent of the population lives in the southeast of the country, where Beijing time fits just right. Opponents say that for this convenience, people in the west spend the whole year jet-lagged against the sun, and even a simple “see you at ten” needs an extra question. Both sides have a point.

One last little secret: Beijing time is not actually made in Beijing. It is produced by atomic clocks at the National Time Service Center in Lintong, Xi’an, in Shaanxi province, then sent out by radio from Pucheng, seventy kilometres away. So while people in Kashgar wait in the dark for the sun, the “Beijing time” on their clocks actually has its home in Shaanxi.