Osaka ( å é ) is the third largest city of Japan . It is in the Kansai region . Osaka is a city in the Kansai region of Japan 's main island of HonshÅ `` , a designated city under the Local Autonomy Law , the capital city of Osaka Prefecture and also the biggest part of Keihanshin Area , which is represented by three major cities of Japan , Kyoto , Osaka and Kobe .