After Genghis Khan died at the end of LOCH, the Mongols did not launch another assault against the Sung Kingdom until four years into the ROCH narrative (e.g. when Yeung Gor was about seventeen years old). What took them so long to get going on this again? Granted, the death of Genghis Khan was a setback, but not one that should have set them back on this goal for as long as seventeen years. Genghis' death certainly didn't flag their momentum much on their invasion of the Middle East and Eastern Europe, so why did it bring their invasion of southern China to a screeching halt for almost two decades?