Billionaire has spent almost six months in Japan after largely disappearing from public viewJack Ma, the Alibaba founder and once the richest business leader in China, has been living in central Tokyo for almost six months, amid Beijing’s continuing crackdown on the country’s technology sector and its most powerful businessmen. Ma’s months-long stay in Japan with his family has included stints in hot spring and ski resorts in the countryside outside Tokyo and regular trips to the US and Israel, according to people with direct knowledge of his whereabouts. Ma has largely disappeared from public view since he criticised Chinese...