Whats happening with the japanese yen and the carry trade involved there, it is quite scarey to say the least. The value of the yen is very low..when this happened before there was lots of trouble in world markets.
As the yen weakens, investors fear either a rise in Japanese interest rates (or some other form of monetary tightening) or central bank intervention to support the currency. This raises the risk that investors will lose money if they short the yen. So one source of global liquidity dries up. And the danger that this will happen cuts share prices. Further weakness in the yen could hurt global equities.