TOKYO (Reuters) -It's Japan's version of the Fed's Jackson Hole symposium, without the trail hikes or views, and this year's gathering of global central bankers in Tokyo will focus on two uncomfortable realities: flagging economic growth and sticky inflation. The Bank of Japan and its affiliated think tank host a two-day annual conference that kicks off on Tuesday and includes prominent U.S., European and Asian academics and central bankers. While most of the speeches are academic in nature and closed to media, this year's theme looks at "New challenges for monetary policy", specifically how central banks should deal with persistent inflation, downside economic risks, volatile markets and U.S. tariffs.