Tong Man-hak is a carpenter who learned the hard way how to make traditional Chinese two-stringed instruments known as erhu. The 76-year-old, who now lives in Hong Kong, was born in China’s southern Guangxi Zhuang autonomous region during the second Sino-Japanese war and in the 1980s moved to Hong Kong to reunite with his mother.  Tong first made his own erhu when he was in his 60s, after losing his instrument in a railway station during a trip to the Chinese mainland. Without no chance to…