TOKYO (Kyodo) -- The recent Tokyo Marathon featured a nonbinary division for the first time as part of an effort by organizers to be more inclusive of runners with varied gender identities.

Thirty-eight runners, 23 of them from overseas, were registered in the category for the March 2 marathon, which became one of the first races in Japan to take the step, prompting calls for others in the country to follow suit.

"I'm very grateful and excited to be a part of this historical moment," said Cal Calamia, a 28-year-old American who traveled to Japan for the first time to run in the race.

Calamia was born female and ran cross country in high school and university before he started to question his gender.

The avid runner, who underwent chest masculinization surgery, has been actively campaigning for a nonbinary category in races, including in San Francisco, where he currently lives.

"I identify more with masculinity now than when I was assigned female at birth," Calamia said. "But I think that my experience of gender is very expansive and can't be encapsulated by the word man nor the word woman."

"This nonbinary division is so important to me because it allows me to do the thing that I love the most, which is running, while not sacrificing any part of who I am and not having to choose between two options that I feel limit me."

Other races in the World Marathon Majors, comprising seven of the most prestigious marathons in the world, had already introduced the nonbinary option, according to Tokyo Marathon race director Yasuhiro Oshima.

The Tobetsu Sweden Marathon in Hokkaido was the first to introduce the segment in Japan in 2023, while the Hokkaido Marathon a year later set up an "open" category which drew around 500 entrants who opted not to be distinguished by gender or age.

With around 38,000 runners, the Tokyo Marathon is the biggest major race in Japan and Calamia believes its impact is "going to be massive" at a time when the gender identity of athletes has become a heated political issue in the United States.

"It reinforces trans and nonbinary people's existence in the global conversation, and especially right now in the United States, that conversation about our inclusion is not looking good with our new president," he said.

Oshima was hopeful the Tokyo Marathon would be only the first of many to implement the same classification.

"I hope there will be more people who understand the issue in Japan, in order to let those participating express themselves confidently," he said.