Dear Alice,

It has been my great pleasure, these past few months, to watch from my window the total destruction of a large building. The work started with three hydraulic excavators that carefully crushed their way down from the roof. Now I'm watching a beautifully orchestrated parade of dump trucks that come to carry away the rubble. The comings and goings of these big trucks reminded me of a question I've had for many years: What the heck are those prominent markings you see on dump trucks in Japan?

Dean L., Tokyo

Dear Dean,

Those markings are called danpuka hyoji bango (dump-truck identification numbers) and are required by a 1967 law with a name so long and cumbersome that it's abbreviated for convenience as the danpu kisei ho (dump-truck control law). The law was promulgated during Japan's period of high economic growth after a number of hikinige (hit-and-run) accidents involving dump trucks. The idea was to make drivers of these big trucks more accountable for safety by making their vehicles identifiable even at a distance. The required markings, painted on the side and back panels, are bigger and far more visible than what's on the license plate.

Before I get into details, let me digress for a minute on nomenclature. In Japan, a truck with a back end that can be tilted backward for unloading is called a danpuka. That may sound like it comes from the English words "dump" and "car" but it's actually wasei eigo (made-in-Japan English). In American English, these vehicles are called "dump trucks." In Britain, they're "dumper trucks." The phrase "dump car" does exist in English, but it refers to a type of railway freight car.

Interestingly, and as those of you with Japanese-speaking toddlers of the male persuasion probably already know, Japanese truck nomenclature borrows widely and apparently haphazardly from other languages. For example, the general word for a truck is torraku, from the American-English word "truck." But what I call a tank truck is a tanku rori in Japanese, apparently on loan from the British-English word "lorry." A horse carrier, meanwhile, is a baunsha. And a garbage truck is a jinkaisha. Both of those are written entirely in kanji, without so much as a whiff of English, and with the readings derived from the Chinese pronunciation.

But getting back to your question, the markings on dump trucks always start with two kanji followed by another kanji inside a circle and then a series of numbers. The first two kanji indicate the unyu shikyoku (vehicle registration office) at which the truck is registered. There are 91 of these offices around the country, but some get more dump-truck registrations than others.

In the Tokyo area, you're most likely to see dump trucks registered in Adachi Ward because it has a high concentration of construction companies, or in Narashino and Sodegaura in Chiba Prefecture. For years now, Chiba has been cutting down its mountains to provide fill dirt for land-reclamation projects in Tokyo Bay, including the expansion at Haneda airport. This is big business for dump-truck operators, which is why so many are located in Chiba. In Kansai, dump trucks are most likely to be registered in Himeji, Nara or Wakayama.

The kanji in the circle indicates the type of business operating the truck. There are seven categories, each with its own kanji mark. An example seen frequently is the character for ken in kensetsu (construction). The numerals that follow are the truck's registration number.

So taking a look at the truck in the photo accompanying today's column, those first two kanji tell us the truck was registered in Narashino. That place name is actually written with three characters but the allowance is for two so only the first two characters are used. The kanji in the circle means "other" which means the business running the truck doesn't fall into any of the other six categories; it's probably a rental or operated by a local cooperative.

By this point in my research I had gained a new appreciation for big motor vehicles, so I trucked on down to the Japan Trucking Association's headquarters in Shinjuku. The first thing I learned there is that Japanese truckers feel decidedly unappreciated; I got a big-rig welcome from JTA's director of public relations, Isao Nagashima, who was more than happy to provide background and statistics.

"People don't realize how dependent this country is on trucking," he complained. "Trucks handle about 90 percent of domestic freight, which means that if trucks ever stopped rolling there'd be nothing on the shelves at convenience stores, no medicine in hospitals and no fish at the Tsukiji fish market. Even so, consumers and businesses take trucking for granted."

What's more, Japanese truckers have a tough job, Nagashima asserted. "Our roads are generally narrow and congested, and there are few places trucks can stop or wait. Yet customers expect deliveries on precise schedules, often granting a window of as little as 15 minutes during which delivery must be made."

The average age of truck drivers has been rising, and almost 30 percent are now in their 50s or older. "We can't attract young workers because wages are below average. And it's expensive and difficult to get a license," he explained. "What will happen when our current drivers get too old to work?"

Aiming for a little understanding, JTA has launched a public-relations campaign complete with animated videos posted on YouTube. "We want people to understand that trucks are part of the infrastructure that supports their daily lives, just like the gas and electricity lines," Nagashima told me.

In fact, trucks play a vital role when fixed infrastructure is knocked out by disaster. When an earthquake struck Kobe in 1995, 40,000 trucks from around the country were mobilized to bring in water, food, fuel and medical supplies. Truckers hold regular training exercises with local governments, police and other agencies to practice response to earthquakes, oil spills, torrential rains and even volcanic eruptions.

Check out the Japan Trucking Association's videos at www.youtube.com/user/JTAvideo. Two of the three have English subtitles.