The handshake in Beijing between Xi Jinping and Shinzo Abe marks an important moment in the hitherto fraught relationship between China and Japan. The Chinese president and Japanese prime minister talked on Monday for only 25 minutes on the margins of the Asia-Pacific Economic Co-operation summit. Judging by the body language, their encounter could not have been more frosty. But for the past two years, relations between the two governments have been minimal, bringing both close to armed conflict. That