The "you can only get good Chinese food in China" mentality is irrational, narrow-minded, and shows limited understanding of the cuisine. Often ingredients used in Chinese cuisine are imported from Japan or other parts of Asia before being processed/prepared/dried and packaged for sale in China. Many of these products are then re-exported for use in Chinese restaurants and for sale in Chinese markets throughout Asia and the rest of the world. So, in many cases the ingredients used in Chinese restaurants in Tokyo and other places are identical to those used in Hong Kong.