More than 600 years ago, Chinese navigators recorded a sea route from Fujian to the Ryukyu Kingdom. Along the way, they noted an island now known as Diaoyu Dao. What can that ancient manuscript tell us today? Experts from Oxford University and China examine how one navigation manual became part of the historical evidence supporting China's claims to Diaoyu Dao. Watch “Diaoyu Dao: Small Islands, Big Stakes,” only on CGTN.