The Beginnings of the Breakthrough with Drifter?

Some of you may remember the post I did a while ago about how Pie had a major breakthrough when Heather got his breathing going again at the canter - here's the post.  Last time I was up, Heather and I were discussing Drifter's reluctance to "let go" - he's having difficulty connecting his body from the front to the back and mentally he's not really softening even when he's compliant.  I wondered if he were really breathing - failure to breathe correctly - it's easiest to detect and fix at the canter - as that is often a sign of a horse that's tight and "closed". I got a very interesting message from Heather this evening - she worked with him on the line today - she usually does just ground work with each horse once a week - I'm quoting from her e-mail and don't think she'll mind:

Checked in on Drifters breathing today. I had done this with him shortly after he got here, and he was breathing really well. But since we are "pealing the onion" with him, I wanted to check again now that we have gotten down a few layers. Interestingly enough, he was holding his breath today. I could hear it at the trot even before I asked him to canter. When I first asked him to canter on the line, he was so uptight he couldn't canter right. He was crossfiring and counter cantering, breaking down into the trot...I just kept asking him for canter again every time he lost it. Whether he was crossfiring, counter cantering, or cantering correctly, I only wanted canter, and didn't put any pressure on him as long as he did so. After about 10 minutes of this, his breathing started to come through, and by 15 minutes he was breathing with the normal, quick and steady rythm. Once he was breathing, he automatically corrected and softened his canter. Correct leads, and nice even stride. Once he was breathing well one direction, we went the other way...it only took about 5 minutes in the second direction, but we went through almost the identical process. He was pretty stuck...he looked different afterwards...almost more "open", and much softer. I am so glad that I checked in on this with him again...my hope is that this will help us break down some of those internal/mental walls he has up. I will check in on this again before I ride him tomorrow.

I think when we weren't initially asking him for much, he was able to (perhaps) conceal how he was doing and feeling, but as we've asked more, the inability to "let go" and be soft in mind and body has been holding him back - hence the issue with canter on the line today.

I think this may be the beginning of the breakthrough we've been looking for with him . . . I'm very fortunate to have a trainer as skilled as Heather to work with him and get him past this to a much better place.  I can't wait to get up there on Wednesday to see how he's doing!