North Koreans in Japan remain loyal to Pyongyang
Above the blackboard, gazing out over the classroom of students hunched over their books, are framed portraits of North Korea's Dear Leader, Kim Jong-il and his father, the country's dead but Eternal President Kim Il-sung.
Beneath them the boys are dressed in dark blue blazers, the girls in traditional Korean costumes.
All the lessons are in Korean - it could be a school in Pyongyang.
But the Tokyo Korean Junior and Senior High School is in Japan.
It's one of dozens, from kindergartens to university, for Japan's ethnic Koreans supported by North Korea.
"From 1957 to this day North Korea has been sending us money every year - hundreds of millions of yen in all," says the deputy headmaster, Yun Te Gil.
"North Korea really helped us out during the very difficult times that we had. The students all go to North Korea on a school trip in their final year. That's the kind of relationship we have."
Hundreds of thousands of ethnic Koreans were brought to Japan as forced labourers or migrants when the peninsula was a Japanese colony before 1945.
Some have taken Japanese citizenship, others have South Korean passports, but a significant minority remain loyal to Pyongyang.
They are the people who send their children to the schools, which are run by Chongryon, the General Association of Korean Residents in Japan.
The organisation says its guiding principle is "Juche", the philosophy of self-reliance developed by North Korea's founder Kim Il-sung.
"They want their kids to learn to be a Korean, learn Korean ethnicity," says the deputy headmaster, Mr Yun.
"When you look at schools in Japan these are the only ones that can teach children to be Korean."
The lessons include the Korean language, history, as well as Japanese.
In the afternoon the students practice playing traditional Korean instruments, some of the girls learn how to dance in unison, in an echo of North Korea's huge mass displays.
Japan has always been uneasy about these outposts of North Korea in its education system.
And the row over school funding has brought the Korean schools back into the spotlight.
The government has excluded them from new subsidies which make high school education in Japan free.
There have been protests from some ethnic Koreans, who say its another example of the discrimination they have suffered.
"In the neighbourhood where I live people are very nice," says one of the students Kim Sul-a.
"I wear traditional Korean clothes as a uniform when I come to school. Everyone notices but they don't say anything, they accept me as the way I am.
"But when I am on the train I can feel people stare. I can feel the discrimination in those stares."
The students are growing up in Japan, but with their hearts in Korea.
But theirs is a complex identity.
The families of most hail not from what is now North Korea, but from South Korea.
Their grandparents and great-grandparents left before the Korean War, which divided the peninsula.
Their loyalty to North Korea and Kim Jong-il is because they hope to see it unified again.
"It's not that we regard them as Dear Leader," says Ri Song-chan, a burly member of the school rugby team.
"But we are taught in school, and it's something I believe to be important, to have pride in being Korean.
"That's the ideology, if you trace it back, of Kim Il-sung and now Kim Jong-il, and North Korea. So I do respect that ideology."
The Korean schools were where members of the Lee family got their education.
They are very proud of their roots, and take part in traditional Korean dancing at the weekends.
But like many other ethnic Koreans in Japan, these days they are feeling less certain of who they are.
In fact between them they've got three nationalities.
North Korea's nuclear tests and its abduction of Japanese citizens in the 1970s and 80s to train its spies, undermined support in the community.
And after the sinking of the South Korean warship, the Cheonan, in March, blamed by an international investigation on North Korea, Lee Yonghwa found he was no longer welcome in South Korea.
"I thought that we should not be too hung up about our nationality," he says.
"By changing to a South Korean passport I can travel to South Korea. And I can show them that there are a group of us in Japan who are keeping up the traditions of Korea."
Lee Yonghwa's sister opted to become Japanese, but his brother disagrees.
"What I believe in is a unified Korea," says Lee Seongho. That's why I didn't switch and stayed being a North Korean."