Hong Kong's border: Virus quarantine makes boundary real for crossers Hong Kong's border with mainland China is a de facto international boundary under the "One Country, Two Systems" model, which lets the city maintain its own liberties and free market economy. The Hong Kong side -- tens of kilometres from the city's downtown -- is predominantly rural while the Chinese side is dominated by the urban sprawl of Shenzhen.\\n\\nIn a major escalation of its battle against the new coronavirus, Hong Kong has said anyone arriving from the mainland from Saturday will have to undergo 14 days of compulsory quarantine. IMAGES of Hong Kong's border with China, passengers heading to border crossings