Tuyen Le, a second-year university student, was near Kasumigaseki metro station on his way back to his apartment as midnight approached. It was the usual time for office workers in Tokyo to return home in the city's suburbs after work.
Seeing a 24/7 restaurant, he walked in to eat after a tiring day at school and part-time jobs.
Then things took an ugly turn.
He said: "I was eating when a Japanese man walked in and screamed into my face: 'Go back to your country, you foreigners always do illegal things. You don't deserve to be here!'"
He felt embarrassed but mostly sad, he said.
"It's not out of nowhere that when the Japanese media covers news about thefts of poultry and fruits where the thieves have not been found, social media would allude to those with 'Nguyen' in their names."
There are around 433,000 Vietnamese living in Japan, accounting for 15.7 percent of all foreigners, according to the Immigration Services Agency. They top the list of foreign nationals who break the laws, the Ministry of Public Security said in June.
Tuan Anh, who's been living in Tokyo for 10 years and works at the ASEAN-Japan Center, said the issue is a deep-rooted one, having to do with apprenticeship and unrealistic expectations migrant workers in the country have.
By June 2021 there were around 202,000 Vietnamese technical apprentices in Japan, or 63.8 percent of the total number in the country, according to data from the Japan International Cooperation Agency.
Eighty percent of them had to borrow ¥674,000 (US$4,680) on average to make ends meet in Japan, a Nikkei survey revealed.
But some apprentices, on arriving in Japan and becoming disillusioned with the realities of life, become criminals.
"They would have incurred huge debts to get to Japan, and disillusionment coupled with those debts often lead them down the path of crime," Anh said.
The number of Vietnamese committing crimes in Japan has been on the rise in recent years, the police said.
In 2020 there were around 600 cases of Vietnamese apprentices committing crimes, a 60% increase from the previous year, they said.
Vietnamese were also involved in 60% of thefts and 35% of brawls involving foreign nationals.
Hiromu Shimada, 31, manager of a company that supports foreign nationals based in Tokyo, said the process of recruiting foreign apprentices is not good enough. Many of them are manual workers with poor prospects and modest education, run up huge debts to get to Japan but get paid poorly, he added.
Tuan Anh said companies should be transparent about income and provide training to ensure Vietnamese apprentices adopt proper skills and language capabilities, which will help reduce crimes.