If you are at this page, that means you either have won or lost the game. Here are the sources that I used to create the decisions - any of them would be a great place to start to learn more, or to check my facts. I have also found that the Wikipedia pages for Mongol Conquests are often quite in depth, although due diligience is required to follow up on sources. With very few first hand accounts of Mongol conquests still remaining, scholars can often differ on the details, and Wikipedia normally only presents one viewpoint.
Some may find it interesting that I chose the easy level to be attempting to avoid getting conquered, while the hard level was attempting to conquer. Afterall, the real life outcome of these events were reversed. First of all, there are simply more decisions that lead to a losing scenario in the Conquest of the Jin level, meaning it is inherently harder. More importantly though, I did so becuase I find the decimation of Khwarezmia to be one of the most interesting examples of hubris by a ruler. If the scholars and Mongol accounts are to be believed, Genghis Khan really had no intention of conquering them. Therefore, I picked it as the easy level. All you have to do to win is act rationally.