This morning I was doing my usual warm-up sequence, a few bits of which involve the turning of the torso (sort of like silk reeling without the weight-shifting - the weight stays centered). At the moment, my main focus when doing these exercises is the use of the knees and kua to drive the movement.
Having done a lot of reading and investigation on the subject, I decided that the turning of the trunk should be facilitated by one knee going up while the other goes down, and by the turning of the femur heads/kua. Whilst focusing on these elements, I ended up getting into a sort of movement that I can only, and perhaps inappropriately, describe as 'skiing without snow' (and indeed without moving forwards). I could feel a definite spiral of each leg as the trunk turned from side to side.
(As an aside, this leg-spiraling business was a source of great confusion for me about 6 months ago, when I couldn't really work out how a leg could spiral given that its feet were firmly attached to the floor).It was interesting how the muscles surrounding the kua really felt like they had been used after I'd finished - not something I normally notice. It's also interesting how much looser and more free my kua feel than they did a few month's back - it's always good to feel some actual physical progress with my Taiji.
This is definitely an area I'll be focusing on over the coming weeks, with the intention of improving the kua flexibility even more, and perhaps more importantly adding some finer control to their movements.