Today, messages are mostly composed online and transmitted digitally before being printed out and hand delivered. In Japan, senders can choose from among a variety of fonts and elegant card stocks and select an accompanying gift from catalogs full of luxury goods and branded items — Disney and Hello Kitty are popular. Flowers or stuffed animals are common choices for weddings, incense sticks for funerals.

Payment schemes have also evolved: Instead of being charged by the character, as in the old days, customers are billed at a fixed rate for a fixed number of characters, and pay extra if they go over.

The telegram’s essence, however, has remained: a concise message printed on a small card and (relatively) swiftly delivered.

The telegram’s transformation into a vessel of etiquette was a decades-long process. Telegram use peaked in Japan in 1963, when the medium — then considered the gold standard for urgent communication — was used to send around 95 million messages, according to a government report assessing the recent state of the industry.

By the 1990s, telegram traffic had nearly halved. At the same time, the messages’ content had undergone an unexpected evolution: Nearly all of them conveyed congratulations or condolences.

In 2020, the most recent year for which data is available, more than four million telegrams were delivered in Japan. That makes it the third largest market for the medium behind Russia and Italy, according to statistics provided by International Telegram, a private firm that provides telegram services worldwide. (In the United States, fewer than a million telegrams are sent annually, the company said.)

The bulk of telegrams in Japan are sent by Nippon Telegraph and Telephone, known as NTT. The company, which started life as a state-owned entity, was given an effective monopoly on the telegram business when it was privatized in 1985. In exchange, the company had to guarantee that it would provide the service indefinitely.

Under NTT’s monopoly, the industry stagnated, and the company’s profits from it eventually vanished. But as government overhauls opened the business to competition in the past two decades, a number of small companies sprang up, introducing innovations like online ordering that have helped the industry survive.

For these firms, telegrams remain a moneymaking niche business.

Keisuke Yamamoto, the president of Roys International, started his company 15 years ago. At the time, he was working in licensing and had noticed a growing demand for telegrams that featured popular brands and characters like Peter Rabbit and Paddington Bear.

At the time, the market was 45 billion yen, he said, or about $325 million in today’s money, and he realized that “snagging even just 1 percent of that would make a successful business.”

He set out to differentiate his company, he said, by pairing the messages with gifts that would appeal to a younger generation. “It worked,” he said. “NTT has stolen our ideas over the years.”

The pandemic has hurt telegram traffic as people have avoided large events like weddings and funerals, but customers have become more likely to send telegrams with expensive presents, said Toshihiko Fujisaki, who heads the corporate planning department at Sagawa Humony, a company that offers telegram services.

The company has tried to bring young people onboard, giving university students the opportunity to experience ordering a telegram. It is also working on a smartphone app.

“Young people don’t know telegrams. They’re used to smartphones,” Mr. Fujisaki said. But compared with getting an email or a text message, “there’s a lot more emotion when you get a telegram.”

For those unfamiliar with the protocol, telegram companies offer online primers on sending messages for a variety of occasions. For weddings, guests should avoid using punctuation, because it could signify bringing something to an end. Senders are also advised to notify the recipient in advance to avoid any potentially unpleasant surprises.

Even as the broader market for telegrams has shrunk, they have remained popular among corporate clients and politicians, who see them as important tools for keeping up relationships.

Politicians send them not just to constituents but to each other, said Mr. Matsuda, the political consultant.

“They send them to each other when they can’t participate in a fund-raising event or when their colleagues get appointed to an important post,” he said.

Mr. Yamaguchi’s scandal, however, may have cooled that enthusiasm. During a recent talk show appearance, Toshinao Sasaki, a freelance journalist and political commentator, said the Unification Church controversy could finally end politicians’ love affair with the telegram.

“Times have changed,” he said, adding, “I think it’s the beginning of the end.”

For Asuka and Hiroshi Kanno, though, the telegram remains something to cherish. They proudly display their wedding telegrams in their living room, and Ms. Kanno said she planned to send one when her own future child gets married.

Still, the couple would never think to send a telegram under other circumstances, she said. When it comes to events like birthdays, “I’d probably go digital.”