By Alex Zolbert, CNN
Tokyo (CNN) -- On the surface, it resembles just about any other high school in Japan -- or any high school in most places around the world.
Students sit quietly studying math, science and English; some struggle to stay focused, looking at the clock and waiting for the bell to ring. When the school day ends, some move out to the sports fields for rugby or soccer practice, while others study music in emptying hallways.
What makes this school different is the pictures of two men scattered throughout the building -- portraits of North Korea's founder Kim Il Sung and previous leader Kim Jong Il.
The Tokyo Korean Middle and High School, which is currently home to 650 students, is one of 10 high schools in Japan with long standing ties to North Korea.
It's something the school's principal, Gil-ung Shin, is very open about.
"Yes, North Korea has given us financial support over the years, sending us money and textbooks," he says.
The school also organizes annual trips to Pyongyang, where students are given highly orchestrated tours of the reclusive North Korean capital.
But the students we spoke with laughed at suggestions from some quarters that they are being trained as spies.
"People think we're being brain-washed. We're not. We just want to study Korean culture and language," 17-year-old Kyong Rae Ha says.