Winter Olympics: why has Eileen Gu’s ‘Chineseness’ sparked a raging debate on nationality and allegiance to China and US?

• The double gold medallist freestyle skier says her heart belongs to both countries but many Chinese and Americans want her to make a choice
• China does not allow dual citizenship but sceptics are wondering if the country has bent its own laws to accommodate the likes of Gu, Zhu and their ice hockey teams