Besides, a visit to Tsukiji is a lark. Tsukiji is open to anyone, and so it has the aspect of an Italian street fair, or rather a dozen Italian street fairs crammed into space for one. You go to Tsukiji as an adventurer, a seeker of early morning exoticism, but such is the pace of business that that no one has time to pay you the slightest attention, unless you happen to be in the way. Only toward the end of Tsukiji's day (around 8 in the morning), will things have slackened to the point that Tsukiji people will have time for a cup of coffee or a can of beer and gentle jokes about your earnest curiosity.

"Where do those come from?" you ask, pointing to a tray of prickly black mollusks as big as softballs.

"From the sea, I suppose," says the grizzled stall owner with a wink. "Can't hardly find that sort of thing in the mountains anymore." In fact, as you find out later, the mollusks are found in only one place in the world, off the coast of Ceylon, and they are available for sale at only one place, right here. To the people who work here, Tsukiji - although it is the largest of Japan's 50 or so municipal markets and quite possibly the most sophisticated market in the world - is a perfectly ordinary place to work, and this in the end may be the most extraordinary thing about it.

A third of all the fish consumed in Japan (and Japan consumes a sixth of all the world's fish) comes through Tsukiji - more than 2,500 tons a day. Such is the drawing power of the market that it is not unusual for a catch of high-grade fish taken off the coast of Kyushu to be iced and rushed to Tokyo to be sold the next morning to buyers representing a fish wholesaler in Kyushu. Tsukiji is as efficient as an electrical circuit. It can put a lobster crawling on the ocean floor of Gloucester, Massachusetts, on your plate in Tokyo in 24 hours.

The Central Wholesale Market (Tsukiji's formal name) stands on land reclaimed 300 years ago from Tokyo Bay. It occupies about as much space as the grounds of the football stadium of a large American university, but on an average day 17,000 trucks come and go through its two gates, to say nothing of the battalions of motorcycles, bicycles, and solid-tired delivery carts that fill any remaining gaps in the swarm of traffic.

The market is organized into tiers. Only seven old-established wholesaling companies called niyuke are authorized to buy directly from the boats. The niyuke sell to second-level wholesalers called nakaoroshi. Each of the 1,152 authorized nakaoroshi, most of whom specialize in a particular species of fish, is allotted just seven square meters of selling space under Tsukiji's creat curving sheds. This tiered organization insures that fish change hands at least three times before they even leave the gates, but such is the secret of Tsukiji's efficiency.

The classic Tsukiji set piece is the tuna auction, which begins around 5 in the morning and continues until 6 or 6:30. Most of the tuna are frozen, because freezing doesn't significantly affect the taste of such a large, red-blooded fish. Hundreds of headless and tailless carcasses frozen as hard as bricks, some from as far away as New York and all dabbed with runes of red paint to indicate their weight and provenance, are laid out in rows on an open expanse of cold concrete out back by the river.

An eerie fog emanates from the frozen tuna as the gravel-voiced auctioneers get to work. Under the dim lights it seems the scene of an ancient druidical rite. The auctioneers communicate with the buyers in a series of smirks and twitches - ordinary language is too languid to sell a tuna every four seconds. The concentration of the auctioneers is so intense that sweat pours down their cheeks, even in the dead of winter.

Some nakaoroshi will buy just three or four perfect specimens of tuna every day, which they take back to their stalls, cut up with long swords, and arrange under lights on a bed of ice, like diamonds. The very best tuna goes for 10,000 yen wholesale, six or seven times as expensive as premium beef.

Tsukiji handles about 400 species of fish, and most are kept alive in plastic tubs of running water (which is why everyone wears rubber boots), so they can be killed at the last possible moment, by a needle through the central nerve. It is felt that the taste of a fish which has been allowed to expire on its own is less well-defined.

It is not necessary to arise at the crack of dawn to see Tsukiji in action. If you get there by 6 a.m., you'll see whole operas. By then, Tsukiji's little shops are serving bowls of Chinese and Japanese noodles and selling buckets and fish gaffs and thick felt soles to go inside rubber boots. Tsukiji's rhythm is six hours out of synch with the rest of the city.

There is something delightfully raffish about sushi for breakfast, like Champagne and strawberries. A sushi breakfast breaks the routine, jars you out of the tracks. A good place among many good places, for Tsukiji knows its fish, is Sushidai, well known to everyone who works here. Sit at the counter and order jo-zushi, the top course, for 2,500 yen, then order a la carte after that to calm what will surely be a rousing appetite.