me opines that yue fei's recapture of khaifeng from the jin would have forestalled the piecemeal divide and conquer strategy and destruction of the jin then the sung by the mongols. a reunited northern and southern sung under one dynasty would pose a greater challenge for the unstoppable mongol horde. or at least, southern sung could have aided the jin when it was under onslaught by the mongols. mongols were the greater hegemony, threat and danger to the sing sung song than the jin.