Aboard one North Korean submarine captured by South Korea last year, “all the radar, GPS and computer terminals were made in Japan,” says Ichita Yamamoto of the ruling Liberal Democratic Party. He says Japanese technology is also used in North Korea’s Taepodong missile, which is said to be capable of hitting targets as far away as Alaska and Hawaii.

Last week the young lawmakers presented legislation to block the sale of any off-the-shelf item deemed useful for North Korean weapons. But Japan has a history of lax export controls. And the weapons builders are finding more and more uses for civilian technology. Which explains why Akihabara has become North Korea’s Los Alamos.