For tourists and residents alike, the quintessential image of Tokyo is of a city lit by artificial light. As soon as twilight gathers, the central shopping and entertainment districts of Shibuya, Shinjuku and Roppongi are awash with neon, shining from each shop and office, even turning the night to a purplish haze.

This image, in fact, aptly describes any city in Japan, from Sapporo to Naha. Few seem to wonder why the country spends so much time in the dark, whether it is desirable to expend so much energy on illuminating it, or what the alternatives might be.

During the last weekend of this month, throughout the developed world, residents will turn their clocks and watches back by an hour. This will mark the end of a summer characterized by long, light evenings, enabling citizens to work and play by natural light. Of the 30 OECD countries, 27 have opted to introduce daylight-saving time from April to October.

In Japan, sunset still comes early. Even in June, it is dark by 8 p.m., when many are still at work in artificially lit offices, while others are heading for bright “izakaya.” The sun has risen by four in the morning; daylight is wasted while Japan sleeps.

Yet the absence of DST is not only anomalous but irresponsible in a time of profligate energy use, diminishing resources and global warming. Worldwide, environmental issues are climbing the political agenda. In Germany, thousands of houses are being built to the “passivhaus” standard: these are so efficiently insulated that they can be warmed to a comfortable temperature only by body heat and sunlight.

Even the U.S., which has not ratified the Kyoto Protocol, is showing new signs of environmental consciousness. California’s maverick Republican governor, Arnold Schwarzenegger, has just implemented legislation to promote solar energy use, and to reduce greenhouse gas emissions by 25 percent in 20 years.

Schwarzenegger was able to take popular support for this measure for granted. California is plagued each summer by blackouts, when demand for air conditioning outstrips the electricity supply. Tokyo, so far, has suffered only occasional power failures, mainly when safety concerns have led nuclear power stations to run at less than full power. But these will become more numerous if demand for energy continues to rise.

Certainly, demand for energy is rising. Japan was the host of the 1997 Kyoto conference on climate change, and an enthusiastic signatory to the resulting Protocol. Under its terms, the country undertook to reduce greenhouse gas emissions to 6 percent below 1990 levels by 2010. Instead, emissions have risen by 8 percent.

The government has run a campaign, “Cool Biz,” encouraging workers to shed jackets and ties in summer. But this amounts to gesture politics considering the energy expended illuminating cities.

The Japan Productivity Center calculated that moving the clocks forward an hour between April and October would save 40 tons of carbon dioxide emissions daily. The economic effect is harder to gauge. Some have suggested that citizens will take advantage of lighter evenings to leave the house, and that shops will consequently see an increase in profits.

Others argue that the heat of the Japanese summer may keep people indoors. Even so, the Productivity Center estimates that the shift to DST would boost the yearly nominal Gross Domestic Product by 0.2 percent.

Why then has such a common sense measure never been implemented? Japanese opponents of DST tend to protest that adjusting clocks would be inconvenient.

But in an article last year in this newspaper, Mayumi Negishi traced the real roots of this antipathy to the Occupation, which, between 1948 and 1952, imposed the system on Japan.

DST was seen as a symbol of foreign rule, a perception owing less to the mere fact that it was an American initiative than to the ham-fisted way in which it was introduced. Clocks were moved forward abruptly on May 1, 1948, only three days after a bill to that effect had been passed in the Diet. No attempt was made to argue a case or to win over a skeptical public. In 1951, in the dying months of the Occupation, the Diet passed a bill to abandon DST. It has never been restored.

Renewed debate last year in the Diet was shelved when then Prime Minister Junichiro Koizumi called an election to confirm support for his plan to privatize Japan Post. Many of the leading supporters of DST were also opposed to postal privatization, and some subsequently lost their seats. For the moment, therefore, the prospects of its implementation seem dim.

But in the absence of direction from central government, businesses and local governments are taking action. The case for DST is particularly strong in Hokkaido, where summer daylight hours are especially long. Since 2004, many firms and government offices there have voluntarily adopted a working schedule equivalent to DST, instructing their employees to arrive at work and leave an hour earlier than normal during the summer months.

This year, on June 21, the city of Oshu in Iwate Prefecture opted unilaterally to move its clocks forward an hour. One may hope that such grassroots actions will continue to spread south. But it will take legislation to guarantee a significant effect on energy consumption.

There are few logical counterarguments. Historically, opposition to DST was strong among farmers, who tended to stop work at dusk, and who feared that longer daylight hours would mean longer working hours.

But numbers engaged in farming have now dwindled to around 5 percent of the Japanese population. More recently, opponents in the Ministry of Education have argued that longer daylight hours would distract schoolchildren from their homework. That may be true, but most Japanese children pursue their after-school studies at “juku;” and they would be safer walking home in daylight.

Some might complain that evenings would be too light for “Obon hanabi.” Yet the United States celebrates Independence Day with fireworks, not long after midsummer, in a country stretching far further north than Japan.

There remains the counter-argument of custom: those complaints about the inconvenience of changing clocks. This is a change the rest of the developed world performs twice a year without complaint, but DST is likely to remain unpopular in Japan until its case has been argued more clearly.

Still, there might be a creative way of neutralizing such complaints. DST is generally a policy of temperate regions, where there are sharp differences between daylight hours in winter and summer. Countries in equatorial latitudes have never adopted the system.

But visitors to the Malaysian capital, Kuala Lumpur, will notice that sunrise and sunset occur, year round, at seven in the morning and evening — not at six, as they would do if midday was truly the middle of the day. This is because the city is at the westernmost edge of a country that stretches for around 2000 km to the east.

This means that Malaysia’s most populous regions benefit throughout the year from an extra hour of evening daylight.

Though this is not a deliberate strategy on Malaysia’s part, Japan might consider following the Southeast Asian country’s lead. European nations put the clocks back in winter because they are relatively far north: permanent DST would mean dark winter mornings, inconvenience for farmers and more deaths on the road. Tokyo, on the same latitude as Los Angeles and Algiers, enjoys proportionally longer hours of winter daylight.

Much of Japan is further south again: the southernmost islands of Okinawa stretch almost to the tropic of Cancer. Even the northern tip of Hokkaido is further south than Paris. Ninety-five percent of Japanese live in latitudes that might benefit from perpetual daylight-saving time.

I suggest that the Diet consider turning the clocks an hour forward in April. Once that is done, to avoid any further inconvenience, they should stay like that forever.

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