It’s not that there is anything bad about your hair, the police officer politely explained to the young Black man as commuters streamed past in Tokyo Station. It’s just that, based on his experience, people with dreadlocks were more likely to possess drugs.

Alonzo Omotegawa’s video of his 2021 stop and search led to debates about racial profiling in Japan and an internal review by the police. For him, though, it was part of a perennial problem that began when he was first questioned as a 13-year-old.

“In their mind, they’re just doing their job,” said Mr. Omotegawa, 28, an English teacher who is half-Japanese and half-Bahamian, born and raised in Japan.

“I’m like as Japanese as it comes, just a bit tan,” he added. “Not every Black person is going to have drugs.”

Racial profiling is emerging as a flashpoint in Japan as increasing numbers of migrant workers, foreign residents and mixed-race Japanese change the country’s traditionally homogenous society and test deep-seated suspicion toward outsiders.

With one of the world’s oldest populations and a stubbornly low birthrate, Japan has been forced to rethink its restrictive immigration policies. And as record numbers of migrant workers arrive in the country, many of the people tidying up hotel rooms, working the register at convenience stores or flipping burgers are from places like Vietnam, Indonesia or Sri Lanka.