DXJ trades like any stock trades and it's speculation that swings the price just like any other stock in the market. Because it's value to shareholders is based on where the Nikkei advances or decreases, those buying/selling these shares will use the potential for the Nikkei's advance/decline as a basis to buy or sell, and this buying/selling pressure on DXJ is what actually moves the share price. I have seen more than a few times, where the Nikkei will be up or down 250 to 320 points the night before, and DXJ will open up flat to slightly up or down a nickel. If you are buying DXJ for a quick round trip trade,it's really not as good of a vehicle as using the ETF that allows you to trade Yen/Dollar movement. There you'll get your pure-play on Japan.