Someone just puked up a boatload of Yen to buy pretty much every other F/X pair. And in the process the DXY getting weaker, as the EUR is 57.6% of the DXY while the Yen is just 13.6%. Nothing like buying Euros against Yen, weaken the Dollar and make stocks shoot up.
In a nutshell this is how you ramp the market: Sell YEN, Buy EUR, weaken DXY and send stocks higher. Nothing more to it.