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Jack, a character in Calvin Trillin’s comic Tepper Isn’t Going Out, sidles up to a midtown Manhattan sushi bar and orders the special—“And make that medium well.”

Jack’s fear—trichinosis—is overblown, of course. All the same, after several weeks of poking around where I wasn’t supposed to, talking to a raft of sushi suppliers and sushi restaurant owners and sushi chefs, asking the questions you simply don’t ask (about freshness, about what gets shipped when)—an investigation, by the way, no less delicate and shadowy than ferreting out the truth behind the Watergate coverup, and with many of the same roadblocks (“Why you want to know these things?” Click!)—I’m beginning to wonder if, in his general skepticism, Jack might not be onto something.

I’m not talking about health concerns—nothing so simple or obvious as that. I’m talking about something larger: the mythology of an entire industry. Years after the so-called boom of the late ’80s, sushi remains a phenomenon that shows no signs of slowing down. Chefs and owners alike speak of the increasing sophistication of the American consumer, of the decline of the California roll as proof of our growing taste for the real, raw thing, say, or the burgeoning popularity of fatty tuna as evidence of our more discerning collective palate.

Maybe so.

But what we don’t know about sushi, I discovered, far outweighs the few stray bits of knowledge we’ve picked up over the years. It may also be what keeps sushi, shrouded as it is in mystery and exoticism, so popular.

Myth No. 1: That slice of fish you slurp down in the evening arrived at the restaurant that same morning.

In fact, according to a source who asked to remain anonymous, who has worked on the line at a half-dozen sushi restaurants in the city over the past two decades, “more than half” of the sushi restaurants in the Washington metropolitan area “do not order their fish every day.”

Yama Seafood, based in unglamorous Jersey City, N.J., is the major supplier of fish in the city. It delivers twice a week to the D.C. area, on Tuesday and Friday. The better sushi restaurants maintain a wide and varied stable of other suppliers in addition—as many as nine different suppliers, in the case of Kaz Sushi Bistro. Tono Sushi, in Woodley Park, and Sushi Taro, in Dupont Circle, two of the more popular destinations for raw fish in the city, rely mostly on Yama. True World, based in unglamorous Landover, Md., is a fill-in supplier, according to Tono’s co-owner, Eddie Pongsaku—“in case of emergency.” Sushi Taro also counts on True World for pinch-hitting.

“We buy a lot of fish on Friday,” says Makio Motohashi, the manager at Sushi Taro. This is meant to sound reassuring, but it makes you wonder about Monday.

Myth No. 2: High end = off-the-dock freshness.

Kaz Okochi, with his nine suppliers for the justly revered Kaz Sushi Bistro, has made a commitment to freshness that many others have not. But even he cannot promise miracles. “Not everything at my sushi bar,” Okochi notes, “has come in fresh that day. I don’t want people to think that every single fish in my case comes in every day.”

Take, for example, his tuna, which typically is caught off the western coast of Florida. It’s an average of three days from the time the fish is caught until it reaches the supplier. And then another day, or thereabouts, until it reaches D.C. That’s four days, during which time the fish is frozen. And Okochi is a purist, more demanding than just about anybody else in the city.

Myth No. 3: Savvy sushi eaters can detect a “quality” piece of fish.

Yu Sheon, the owner of Cafe Asia, which has locations in Arlington and downtown, says that a skilled chef can do much to prolong the shelf life of his fish: changing its wrapper frequently—“several times a day, at least,” maintaining a strict temperature, continually washing his hands.

“If you can really preserve it well and nicely,” Sheon says, “you can keep a piece of fish around for a while.”

James Tan, the manager of Dupont Circle’s Uni, notes that once a fish has thawed, it can be kept around “a maximum of three days.” Which means that even at a top-flight establishment you might well be eating a piece of tuna that was caught a week earlier and kept frozen until din-din.

Conveniently, tuna and salmon are the easiest of fishes to freeze. They also happen to be the most popular choices on the menu at Americans sushi restaurants.

Myth No. 4: Color is a clue to freshness.

There is “a misconception,” says Sheon, about “the redness of the tuna. Brilliant red does not necessarily mean fresher.”

In fact, injecting just-caught fish with a red dye is common throughout the industry, as a way for suppliers to make a piece of tuna that much more attractive and eye-catching. Sometimes, Sheon says, sushi chefs can tell a doctored piece. And sometimes they can’t.

Myth No. 5: Sushi is healthy.

Notes Okochi: “I know it’s not unhealthy.”

Forget the usual fear among sushiphobes like Trillin’s Jack. Americans are more likely to poison themselves slowly. The tendency

to order up a mammoth platter of sushi—and nothing else—results in a meal that, while rich in protein, usually contains significant amounts of sugar and sodium thanks to that saucer of soy. And often little or nothing to speak of in the way of vegetables.

So much for those classical Japanese notions of balance, harmony, and symmetry.

Myth No. 6: The more sushi restaurants there are, the better the all-around quality.

Okochi, who came to this country in the late ’80s, says he is surprised by sushi’s continued growth in popularity. According to him, the number of Japanese restaurants in the United States has doubled in the past 10 years. He theorizes that “the quality is slipping” as more and more restaurants open up.

Why is the United States not more like Japan, where you can count on quality sushi even at the littlest hole in the wall?

“Because of the not-very-developed seafood distribution in this country,” Okochi theorizes, adding, “You grow up in Japan, you never see bad fish.”

Uni’s Tan, who once worked with Okochi at Sushi-Ko, argues that things are changing, that increased consumer consciousness is driving an increasingly efficient system.

“The consumer is so much more educated and sophisticated than 10 years ago.” He alludes to the movie Big Night, explaining, “Fifty years ago, you went to an Italian restaurant expecting meat and spaghetti. Now, people know the difference between the pastas. They know angel hair. That kind of thing….Nobody wants California rolls now. They can tell good tuna from tuna that sucks.”

Maybe. But can they tell if their tuna has been frozen? Can they tell if it has traveled four days or more from the time it was caught until the time it hits their sushi bar of choice?

Not yet.—Todd Kliman

Eatery tips? Food pursuits? Send suggestions to hungry@washcp.com. Or call (202) 332-2100, x322.