Tokyo, Sept. 17 (BridgeNews) - Japanese shares fell steeply in morning trade as concerned investors looked ahead to the resumption of U.S. markets later in the day following last week's terrorist attacks. Friday's weak stock performance in Europe, along with the yen's appreciation against the U.S. dollar, also added negative tone. The Nikkei 225 Stock Average closed the session 488.20 points, or 4.9% lower at 9,520.69, after reaching a morning low of 9,447.76.