I'll lead with the obvious one - Why Ancient China?
And I'll answer, why not?

The longer answer; I've loved Kung-Fu movies since I was old enough to watch them (probably a bit before that). The video store on Eastcott Hill in my home town (now sadly gone... the shop, not the hill) was a my hunting ground and in those days Film Certificate ratings were more guidance than actual, you know, rules. So I watched a load of them. Then Jonathan Ross did a Jackie Chan series on the new terrestrial channel in the UK (C4) and I was totally hooked. I studied Kung Fu for a year or two and read a lot of Sci-Fi and fantasy books.
Every fantasy book was set in a version of Medieval Europe... every single one. AD&D ruled the fantasy world. There were some outliers, Elizabeth Boyer's Alfar series for instance, though even those were set in a northern European world (though one I loved for its mysticism and hidden worlds... if you haven't read them, they're worth checking out).
So, my fascination with the Far-East, Martial Arts, Magic all got wrapped up in the setting - I wanted to write something a little different, set it elsewhere, in a different culture. The thing is, people usually prefer to read the stuff they know, so I knew it would be a hard sell.
Link to Guest Post on World-building... may contain spoilers!