Dear Alice,
My husband attended a business dinner late last year at a very fancy traditional Japanese restaurant. At the end of the evening, as he was heading out the door, the kimono-clad proprietress presented him with a gift of a single piece of fruit. It was like a large orange but with a weird pear shape. I've rarely tasted anything so delicious. I looked but I couldn't find it in any store. Can you please find out what the heck that fruit is?

Jennifer H., Tokyo

Dear Jennifer,
That fruit your husband received was a dekopon. And now hold on to your seat, because here comes the juiciest story involving a piece of fruit since that one about Adam and Eve and the apple. Behind that sunny citrus countenance lies a steamy tale of international trade friction, blatant theft and, ultimately, redemption.

Before I get into all that, let me describe the dekopon for the benefit of readers who've never seen one. It's bigger than an orange but smaller than a grapefruit. It's got a funny protuberance at the top. The skin is orange and very thick. It peels effortlessly, is seedless, and is quite probably the sweetest citrus you'll ever eat.

To get some details, I paid a call to Tokyo Seika, the largest produce distributor in Japan and a key player in bringing the dekopon to market. Public-relations manager Kohichi Kato explained that this rising star in citrus got its start in 1972, when scientists at a government research facility tried crossing an orange-tangerine hybrid called kiyomi with the ponkan, a seedy citrus originally from India. While Japan has traditionally put significant resources into plant breeding, Kato said, there was particular urgency in this project.

"At the time, Japan was under significant pressure from the United States to open its market to imports of fresh oranges," he recounted. "The general feeling was that our humble mikan (Satsuma tangerine) would never be able to compete with the big, sweet oranges from California. Unless we could find something new to grow, the entire domestic citrus industry was doomed."

So with great hopes, the new variety, dubbed shiranuhi, was sent out to testing facilities around the country. But every station came back with the same damning results: The yield per tree was a fraction of other citrus fruits. The fruit was inconsistent in shape and quick to rot. The new variety was judged a flop and the scientists went back to the drawing board.

However, a gutsy grower from Kumamoto Prefecture, by chance on a tour of one of the testing facilities, saw something in the odd-shaped fruit and broke off a branch to take home.

"Basically, he stole it," Kato allowed. "It was government property and he took it without permission."

After a few years of fiddling, the grower called sales reps from Tokyo Seika and convinced them the product had promise. They brought it to market for the first time in 1979, but wanted a more memorable name. Someone came up with "dekopon" — a compound of deko (bump), for the lump on its head, and pon, from the first syllable of its parent the ponkan.

There was some initial resistance from upscale retailers, who complained that it sounded vaguely sexual, but consumers seemed to think a goofy-sounding name was a good match for a goofy-looking fruit. In any case, sales rose steadily and pretty soon farmers in other parts of the country wanted to grow it too.

There was one problem: The Kumamoto grower's cooperative had registered the name, so growers elsewhere had to dream up alternatives. For a while there was himepon, tried in Ehime Prefecture, and hiropon, used by Hiroshima growers — until they found out it was a slang term for an illegal stimulant. Eventually, growers came to an agreement whereby anyone can use the name dekopon if they pay a fee and meet certain quality standards.

And so — and here's the redemption part of the story — in less than 20 years the dekopon has gone from an obscure and unloved fruit to the darling of the domestic produce industry.

"Dekopon is the best new fruit to come to market in years," proclaimed Toshio Joutoh, president of Notomijoumata Co. Ltd., a wholesaler in the massive Ota produce market in Tokyo. "It's perfect for sharing, so it brings people together, and the membranes are so delicate that the sections just melt in your mouth."

Dekopon are now grown in 23 of Japan's 47 prefectures, with over 3,000 hectares in production yielding more than 38,000 metric tons every year, according to a census conducted in 2005, the most recent year for which national statistics are available. And the great irony is that if Japanese citrus growers hadn't diversified in response to foreign trade pressure, they'd now be facing a crisis due to global warming. Average temperatures in Japan have risen one to two degrees Celsius over the past three decades, making it difficult in many parts of the country to grow mikan.

"Thanks to the heat-resistance in its genes from the orange, the dekopon can thrive in all sorts of places that have become too hot for mikan cultivation," Joutoh explained. "Dekopon is the savior of Japan's citrus farmers."

You couldn't find dekopon in stores in December because that's the very beginning of the season, when prices are too prohibitive for anything but the gift market. But now supplies are up and prices down. February is a good month to delve into dekopon because many supermarkets run it as a loss leader, at about ¥700 for two. Then come March, prices drop and stay low through the end of the season, which is usually early May.

Puzzled by something you've seen? Send a description, or better yet a photo, with the address where you saw it to [email protected] or Alice Gordenker, A&E Dept., The Japan Times, 4-5-4 Shibaura, Minato-ku, Tokyo 108-8071