China and Japan already together account for more than a fifth of global output, bigger than the share held by the United States or that of Europe. Over three-quarters of that, of course, is generated in mainland China but, contrary to widely held perceptions, the China–Japan economic partnership is one of the biggest in the world.
The bilateral trade relationship is the third-largest in the world, with a US$340 billion trade relationship in 2014. China is Japan’s largest trading partner, accounting for one-fifth of its trade, and Japan is China’s second-largest. Japan is the largest investor in China, with a stock of direct investment at more than US$100 billion in 2014 or US$30 billion more than the next largest source, the United States. But even those massive trade and investment figures understate just how intertwined are these two Asian giants.