Previously, I put forward the argument that Hong Kong’s relevance in China’s opening up lies less in guarding its gateway role and more in developing new forms of partnership. Since then, Hainan has set up distinct island-wide customs operations from December 18. This is a turning point – one that invites Hong Kong to think not only about how to cooperate, but how to co-design the next phase of China’s engagement with the world. Hainan’s transformation is ambitious. Around 6,600 types of goods...