WHAT is great sushi? Of course, said Seki, the chef and owner of Sushi Seki on First Avenue, great sushi needs great fish. But, he continued, great fish is not enough.

"Sushi is so simple that each element must be perfect, and all the elements must be balanced," he said. "Like pizza."

Like pizza, sushi can be downed as a quick lunch or dwelt upon obsessively for a lifetime. Once your sushi consciousness has been raised, it becomes a pleasure to appreciate its subtle distinctions: the rice should be warm, so that the chilled fish begins to approach body temperature before the piece goes into your mouth; nori, seaweed sheets used for rolling maki, should be thin and crisp, instead of tough and leathery; the wasabi and gari (pickled ginger) should be freshly made.

In Japan, aficionados judge a sushi chef by more than the quality of his fish. ("His" because there are almost no women who are sushi chefs in Japan: legend has it that women's hands are too warm to make sushi.) The proportion of rice to fish is carefully considered. Even the arc described by a piece of sushi fish as it rests on top of the rice has a prescribed shape.

"It should have the same curve as the pages of a book, when you open it and place it on a table" said Gen Mizoguchi, the sushi chef at the new Megu in TriBeCa. Traditional sushi chefs arrange the pieces in rows to mimic the appearance of a school of fish swimming.

Despite this cultural and culinary baggage, it is worth noting that sushi began not as an elegant way to eat raw fish but as a way to preserve it. Packed between layers of cooked rice, whole raw fish fermented slowly instead of rotting, becoming lightly pickled. That pickled flavor is still a faint but essential element in sushi. It is why sushi rice is sprinkled with vinegar.

Sushi, at its most basic, consists of a finger of rice draped with a slice of raw fish, ideally in a proportion of about 4 to 1, according to Nobu Ishida, whose Apollo Fish Company, in Maspeth, N.Y., supplies top sushi chefs in New York at Nobu, Masa and Sushi Yasuda.

That proportion is not always observed in New York sushi bars. In the 1990's, sushi lovers had their heads turned by the large pieces of fish served in New York at places like Tomoe Sushi and Japonica.

"Big pieces is the Korean style of sushi," Mr. Ishida said. "There are so many sushi chefs in New York now, and many of them are from Korea or trained with Korean sushi chefs." But Japanese chefs like Masatoshi Sugio of Sushi of Gari on the Upper East Side have now swung the pendulum the other way, toward small pieces that can be eaten in one bite and are thought to be more elegant.

Fish gets most of the attention at sushi bars, but Koji Imai, an owner of Megu and a culinary celebrity in Japan for championing artisanal ingredients, says that rice is the most important ingredient. "The rice comes first, and then what goes on top of it," he said. (The word sushi is a synthesis of the words for rice and vinegar.) Mr. Imai said that the rice for Megu is grown to his specifications, so the quality is assured, but that the wildly varying humidity of Manhattan's weather causes headaches at the sushi bar. "The formula that works for cooking rice in Japan doesn't always work here," he said wearily.

Mr. Imai popped a ball of rice into his mouth, assumed a thoughtful expression and gestured his approval. "A lot of the rice in American sushi bars is cold and sticky," he said. "When the rice is not good, the fish can't be good either."

Mr. Imai's affection for the artisanal ingredients of Japan verges on the finicky (the restaurant recommends different soy sauces for sushi and sashimi), but a taste of Megu's freshly grated imported wasabi root, with its green, bracing flavor, is convincingly different. "I am from Shizuoka Prefecture, where the wasabi here comes from," one waiter confided. "And I never got to eat it there — it's too expensive."

Wasabi was originally added to sushi for its ostensible antibacterial properties: according to tradition, a dab of grated wasabi between the fish and the rice helped street vendors keep their sushi fresh and could mask any developing off-odors at the end of a long hot day. Today, the wasabi most often served at sushi bars is overwhelmingly sharp and not wasabi at all: it is a paste made of mustard, dry horseradish and green food coloring.

True wasabi is not even related to horseradish. It is in the mustard family. A single wasabi root takes about three years to grow to harvest size, making it expensive, about $40 a root. When a sushi bar buys a root, the wasabi is grated to order in small quantities on a traditional grater of rough shark skin. Fresh wasabi has been available in the United States for some time, but most of it is grown in Oregon, and Mr. Ishida said its flavor is not as strong as the Japanese variety. Koji Ohneda, a manager at Sushi Seki who has worked in sushi restaurants in New York for almost 20 years, said: "We used to have the stewardesses from Japan Air Lines smuggle it through customs. We paid them for the service in sushi."

Sushi Seki is notable for the crispness of its nori, the sheets of pressed seaweed that are used to roll rice and fish together to make maki. Instead of the usual resistance and chew, a bite into maki made by Seki, who uses only one name, produces a satisfying crunch. "Of course, the quality starts with the farmer," Seki said.

The seaweed farmer?

"Farmers and fishermen collect the seaweed and make it into a paste, then sell that to the producers," he explained. "That's why some batches are different from others." Tough nori is usually old nori: seaweed, once dried, has a tendency to grab moisture from the air, which makes it soft instead of crisp. Masa Takayama of Masa, like many attentive sushi chefs, toasts each sheet of nori individually, to dry it until crackling and crisp.

But when all is said and done, crisp nori, house-made gari, fresh wasabi and artisanal soy sauce are just supporting players, as the beautifully lighted fish case at Masa reminds you. Raw fish is the star — and, like many stars, it may be older than it looks. Much of the sushi sold in Japan and the United States has been frozen at some point before it reaches the sushi bar, both to preserve its quality and to eliminate the parasites that are common in wild fish.

Naomichi Yasuda, the chef and an owner of Sushi Yasuda in Midtown, says that he ages almost all of his fish after he receives it so that the rigor mortis that affects freshly killed fish has time to pass off. Mr. Yasuda wraps the fish in paper-thin sheets of cedar wood and checks it often, waiting until the flesh is melting but not yet soft or mushy: in most cases, he says, this takes one to two days. "There is such a thing as fish that is too fresh," he said.

original article posted at
 http://www.nytimes.com/2004/04/21/dining/21SUSH.html