Japan on Monday marked its first Coming of Age Day since the age of adulthood was lowered from 20 to 18, but with many 18-year-olds busy finding work or studying for college entrance exams, most municipalities retained traditional celebrations for 20-year-olds.

For around two decades on the second Monday of January, and on Jan. 15 before that, young people whose 20th birthday falls between April 2 the year before and April 1 of that year have attended ceremonies to mark the start of adulthood.

With changes to the Civil Code to lower the age of adulthood coming into effect last April, local governments have been left with decisions over whether to adapt their events.

Participants in Coming of Age Day celebrations at Tokyo DisneySea pose for a photo in Urayasu, Chiba Prefecture, on Jan. 9, 2023. (Kyodo)

Among those that have opted to remain focused on 20-year-olds is Yokohama, which held the country's largest-scale coming-of-age ceremony at Yokohama Arena with some 36,000 people eligible. The event this year was split into five services as part of coronavirus prevention measures.

Yuria Oka, a 20-year-old university student attending the fourth ceremony of the day, said she wants to "work hard while not forgetting to be thankful."

At the "ceremony to commemorate adulthood" in Naka Ward of the central Japan city of Nagoya, participants could be heard saying that being together with their friends was more important than the event's name.

"There was talk of 18- to 20-year-olds all being bunched together, which left me with mixed feelings. I'm glad we got to have an event just with people our own age," Kosei Nishiura, a 20-year-old university student, said with a look of relief.

Some municipalities have made attempts to adapt to the changes, however, with the municipal government of Iga, Mie Prefecture, deciding to hold a ceremony for 20-year-olds on Sunday, with further events for 19- and 18-year-olds coming in March and May, respectively. From 2024, the city plans to hold only the May event for 18-year-olds.

Participants in a Coming of Age Day celebration in Nagoya, Aichi Prefecture, pose for a selfie after the ceremony on Jan. 9, 2023. (Kyodo)

Elsewhere, Misato in the southwestern prefecture of Miyazaki hosted an "adulthood certificate giving ceremony" for 18-year-olds in August, with similar events for 19-year-olds and 20-year-olds held last Tuesday.

As of Jan. 1, there were 1.12 million 18-year-olds in Japan born in 2004, with 1.13 million 19-year-olds born in 2003, and 1.17 million 20-year-olds born in 2002, according to population estimates from the Ministry of Internal Affairs and Communications.

The government revised the Civil Code to reduce the age of adulthood in June 2018 as part of a bid to spur young people's social participation. It was the first change to Japan's definition of adulthood since the code was drawn up in the late 19th century during the Meiji Era (1868-1912).

Revisions to the code and other laws went into effect in April 2022, and they now mean that 18- and 19-year-olds can marry without parental consent and are subject to stricter punishments for criminal offenses, among other changes. Separate legislative changes brought the voting age to 18 in June 2016.

Smoking, drinking and gambling remain prohibited until 20, however.