alternatehistory.com

I'm working on a timeline in which the Korean general Yun Gwan successfully conquers the Liao empire's Jurchen protectorates in Manchuria (he came surprisingly close OTL. For more on that see The Tiger & The Magpie or look him up.)

The thing is, ITTL, the Jurchens, who would have replaced the Liao in 1125 AD, are subject to the Koreans (and have been for about 14 years, which isn't much, but still), so I doubt that (even if a significant amount did move west) they would be powerful enough to conquer the Liao. The Liao would definitely still collapse, being even weaker than ITL. The next option would be the Western Xia, their southern neighbours, but they had terrible military leadership at the time.

So who would fill the power vacuum? I don't want to mess with Mongolia, so as not to butterfly away everyone's favourite horselord. There are the Uyghurs in Qocho, who were in a similar situation to the Jurchens, being one of the collapsing empire's tributaries, there are the Kara Khanids. But both of these would have to conquer the Xia to get to the Liao.

There's also China, but OTL the Jin conquered parts of china, so clearly the Song leadership wasn't exactly great...

Can anybody help? Do any of these make sense? Anybody else who could fill the power vacuum?

Here's a map of Eurasia around then, for reference.
Top