after reading more on this thread, I think the horse is resisting the turns out of willfulness. Call it naughty if you like, but she is carrying her thought through into action, and the more she is successful at it, the harder it is to change.
Personally, I do not think it's a crime to turn her the way she wants. It's not so much that, for example, you go right and she also wants to go right, it's about HOW she goes right. It has to be YOUR idea, your speed, your arc of a circle to follow. So, go ahead and USE her thought to your benefit. Her desire to go that way can actually give you some impetus to bend to your needs.
I started a little on that this Sunday -- I wanted to go left, she wanted to go left -- I initiated the turn, and wanted a nice soft arcing turn --- she turned hard and sharp -- so I started trying to turn her right to go back to where we were and do it again
I kept her head and neck turned to the right, she powered through it going forward/leftish until we got up to the brush line -- I didn't release, but she slowed down a little, and I finally got her to turn right --- right through the brush
Went back to where we started the turn and did it again
3rd time I finally made it to the point I wanted to make it to and made her do a full circle to the right and then back to the trainer
start the turn in the direction she wants to go, but use your inside leg and try to disallow her to "fall in" onto her inside shoulder and cut the corner, or turn around really tight and short, like a gate swinging fast on its' hinges. The trick is to put bend into her body and make her keep her inside shoulder up, meaning, stay even on her shoulders.
do I shift my inside leg forward a tad, and press her shoulder back into place or more inline with where I want it to be?
Once you can feel what it feels like to move a hrose's shoulders over, you'll know when you need to do that, when she is falling in. This is almost the OPPOSITE of the "semi-truck " analogy I was talking about.
That is "falling out".
So, for example. She wants to go LEFT. You try to turn right, she powers through her left shoulder because she wants to go left, even though her neck is sharply "broken", like the semi cab off at angle from the trailer. That's "falling out" through the shoulder. You have TOO MUCH bend. You need to not give her so much left rein so that her neck cannot bend so far off to the right and get that "broken" position. Use your outside rein to kind of create a "wall" against her neck, and your outside leg , too, and your inside rein to tell her to turn right but not yank her neck way over.
I never yank, I pull a little, and let go if she turns -- if not, I pull a little more, and I just keep gradually pulling more and more -- I try to keep it a smooth gradual pull without yanking (mostly because I am afraid that if I yank too fast or hard, she'll flip over her should and take me with her)
for the other one, the "falling in" , the swinging like a gate one. . . . Say she wants to go right, and maybe you start to turn right and she cuts hard and sharp right, the answer is to put MORE bend, using inside leg, more inside rein and maybe move your outside rein off her neck a bit to encourage her to step back onto her outside shoulder. If she moves outward, that's ok. If she disengages, that, too is ok. You get her to stop this idea of powering through the turn, you take back the helm and you can turn, even in the direction she wants to go, but at YOUR direction/speed and quality of movement.
And, when she gives in to this, you give her a bit of rein, give her praise, and let her walk forward a bit .
thanks tinyliny --- great and very detailed advice