The scene is unmistakably Hong Kong. A field of high-class Thoroughbreds thunders down a lush turf straight, the pounding of hooves echoing against a grandstand and a large diamond-vision screen. To a casual viewer with no sound on, this is racing at Sha Tin. But as the horses pull up, no skyscrapers loom over the backstretch, and the stands are desperately empty. There is no Shing Mun River here; it is a barrier trial at Conghua, and for the horses involved, the transition between these two worlds has become part...