In early 1943, Lau Kai-bill answered a recruitment advertisement in Wan Chai for miners to work on Hainan Island.
He left behind his 20-year-old wife and two young daughters and was never heard of again. His infant son had died from an illness at the start of the Japanese occupation in 1941.
'[The family] got a notice saying he was dead a few months later. There was no explanation of what happened or mention of wage payment or compensation,' said Mark Li Kin-yin, his grandson, 48, who is collecting evidence of Nishimatsu's alleged complicity in using forced labour on the island.
'My grandfather was among the first to join. Unlike those who were sent later, they were not forcibly sent to the island.
'But once they got on the ships, they were treated as slave labour . . . People started dying in the first month.
'They were not allowed to communicate with the outside world and were under armed guard. Many were beaten.