As Hong Kong stretches north on grassy plains, and the high-rises thin out into sparse clumps, the length of time between stops increases as your train rumbles along the century old Kowloon-Canton railway. You come upon a thin strip of water – a murky line that marks one world from the next – and beyond that… A city rises before your very eyes. Shenzhen. Belligerently eying the green and the hills… the space… on the southern side of the river. Once beyond the border the buildings are different: Older? Cheaper? Grand but bland. Unmistakably Chinese. And there’s the Commercial City, built on a butt of land that juts cheekily into Hong Kong – five storeys of ‘Copy watch, Sir?’, ‘Come look’, ‘What you like?’, ‘Genuine copy’ with people squatting beside carry-out rice bowls and kids clustered in stairwells playing trumps and dice, rather than locked away in cram schools. It’s another world, for sure.