Japan's workforce is shrinking due to an ageing population and a policy of very low immigration. But though the world's third largest economy needs workers, the government isn't keen on immigration when it comes to filling lower-skilled jobs. A loophole in the rules, however, means every year about 200,000 labourers from overseas go to Japan on its guest worker trainee scheme. Arranged through a network of brokers in countries such as China and Vietnam, workers often find themselves underpaid, and the US State Department categorises the scheme as human trafficking, and points to mass exploitation. Edwin Lane investigates in Tokyo and Gifu, meeting workers from China who are stuck in Japan fighting for their wages, and to lawyers and politicians about what can be done, and asks why Japan is so hesitant to open its borders to more foreigners.

(Image: Tokyo's Akihabara district.Credit: Chris McGrath/ Getty Images)