A worker puts foamed dashi on ramen at Gyorai in Tokyo. (Ko Sasaki/For The Washington Post)

Takeshi Yamamoto’s year started with a bowl of wonton noodle soup in northeastern Tokyo.

The cold sour plum-infused noodles he ate on a recent Monday at Soranoiro, a trendy ramen joint in central Tokyo, constituted bowl No. 359. “It has a fine flavor,” he pronounced after a hearty slurp of the seasonal special. “It’s excellent.”

He had tied a standard-issue large paper apron around his neck — the restaurant is in a business district, and salarymen don’t want to go back to work with splatter marks — and taken a photo of his meal before beginning.

A little more than an hour later, Yamamoto was tucking into bowl No. 360, a steaming bowl of bonito fish soup with chewy noodles at a Chinese-style restaurant a few subway stops away. “It has a really good smell — fresh fish,” he said. “I’d give it 10/10.”

Yamamoto is one of Japan’s “ramen kings” — a self-described noodle-soup freak who has proved his credentials in a nationwide competition involving blind-tasting ingredients and identifying what ingredients are missing from popular soups.

He also could be described as something of a throwback in a country where ramen is threatening to become ho-hum even as its stock rises abroad.

Both the number of bowls sold and the number of restaurants selling ramen in Japan have steadily declined in recent years, according to figures from the Shinyokohama Ramen Museum.

“The ramen boom has ended,” said Ivan Orkin, a New Yorker who first traveled to Japan in the 1980s and now owns two noodle-soup restaurants in Tokyo. “A boom implies that there are new avenues and new growth to pursue, and that’s not the case in Japan anymore.”

Fifteen years ago, one of Yamamoto’s friends began collecting the lids from cups of instant ramen, the staple diet of computer nerds worldwide. The friend amassed enough of them to stage an exhibition, and Yamamoto went with him to the show. The experience whetted his appetite.

“I tried a few different kinds of ramen there, and it made me think I should try more,” Yamamoto said.

And try more he did. That first year, he ate about 500 bowls and developed a sophisticated enough palate to win his ramen crown.

But Yamamoto thought that he had peaked too quickly, that he didn’t have the ramen experience to justify his title. So he started slurping his way around the country. His best ramen year was 2004, when he ate 1,221 bowls — which works out to 3.3 a day.

Now, he averages about two bowls a day.

“I’ve always liked eating,” said Yamamoto, who is 44 and deliberately keeps his schedule free enough — he works as a freelance computer systems engineer — to maintain his ramen addiction. He could euphemistically be called fuller-figured in a country where the average build is slight.

Although few consumers could keep up with Yamamoto’s pace, ramen has become increasingly popular around the world. Japanese noodle-soup shops can be found from Sydney to Stockholm. In Washington, New York and Los Angeles, long lines form at the hippest new ramen restaurants.

The Japanese government is also using ramen as a form of soft power — or at least al dente power. It has helped organize ramen events to showcase the noodle soup in cities including Paris and Hong Kong, part of its “Cool Japan” campaign.

Proponents of ramen are trying to teach foreigners how to slurp — they say it intensifies the taste — and to finish the bowl within five minutes so the noodles don’t get soggy. (Yamamoto was incredulous to learn that Americans can easily spend 30 minutes in a ramen restaurant.)

‘We . . . made them better’

Ramen came to Japan from China. The first known ramen shop opened in central Tokyo in 1910, but ramen consumption really picked up after World War II, when Japanese soldiers returned from fighting in China and started making their own noodles from rationed flour.

Back then, ramen was something made with all the odds and ends left over from other meals, a way to economize and avoid waste. It was the antithesis of sushi — which uses only the finest ingredients and for which less is more — but it still came to be considered integral to Japan’s culinary identity.

Ramen took off as Japan’s economy picked up speed in the 1980s. As more Japanese could afford to travel, they would tour the country trying different types of noodle soups, such as Sapporo’s miso ramen and Fukuoka’s famous thick pork-broth ramen. People in the provinces began to celebrate the uniqueness of their bowls.

Ramen chefs also started to use more expensive ingredients, and the dish became, if not haute cuisine, a kind of delicacy in its own right and a symbol of the country’s broader transformation.

Restaurants multiplied — Tokyo alone has an estimated 10,000 — and chefs started experimenting with different types of broths and ingredients.

The ramen boom showcased the best aspect of Japan, Yamamoto said.

“We took Chinese noodles and made them better. We made improvements to the soup stock. We added lots of ingredients and made it into a full meal,” he said.

‘Everything has been tried’

But now it appears that the noodle soup is coming off the boil for some Japanese.

“Ramen in Japan is no longer considered something fresh or interesting,” said Kenji Chiba, chairman of the Nippon Ramen Association, a group of 500 ramen restaurant owners.

“All the different varieties have been tried; everything has been tried,” Chiba said at the association’s stall at a huge food industry trade show in Tokyo.

Orkin agreed that the soup has become ubiquitous. When he opened his first shop in Japan in 2007, people thought he was crazy to put tomatoes in his ramen. They thought he was even crazier when, at his second shop, he began adding cheese, but it quickly became his most popular dish.

“When I first went to Japan, ramen was popular with salarymen and truck drivers. It was a blue-collar food, a junk food,” he said. “If I’d suggested that a well-dressed woman in high heels would eat ramen, people would have laughed at me. But now ramen has completely permeated society.”

Rikiya Yamaji, a food journalist and ramen critic, is concerned about the lack of originality in ramen these days.

“Over the past few years, many places started to copy a trend or steal an innovative technique,” he said. “So there isn’t any love or passion for ramen, and no respect for other ramen chefs and their originality.”

But some aficionados won’t be discouraged.

Asked at the end of his second lunch what he planned to eat for dinner that night, Yamamoto paused as if to give it some thought before uttering the obvious: “Ramen.”

Yuki Oda contributed to this report.