A packed spade, and two pics the sustainable dressage site (and this is just a cathedral port, not a spade), which is clearly not a fan of spades, but here’s a quote from them as well:
Spanish and Western bitting include even higher and narrower ports, sometimes pointed, tassled, with rolls etc, which would pressure up against the palate quite far back and possibly cause tissue damage if used in the modern dressage riding style in which the rider pulls the reins backwards. They use these bits just because spanish and western riders supposedly do not pull on the reins. This is a self regulating bit. It is made to work in the way that it will apply pressure to the palate by the weight of the shanks. I have superimposed a photo with a catherdral-port bit, both at the vertical, and showing the action when the horse goes above the vertical.
I like the ‘supposedly’ they don’t pull back on the reins. Because the writer apparently doesn’t believe spanish and western riders (and way to group a ton of different types of riders into one category) are capable of being effective riders. But whateverrrr. This demonstrates self-regulating bits. If the horse raises their head beyond a certain point, the port taps against their palate. If they hold their head in a certain position (flexed at the poll) the bit is at neutral.
And I’ll grab some quotes from Jeffrey Mundell in this video explaining the spade:
‘The chin strap, or curb strap, is designed that if you were to pull on this bit really hard, you adjust this curb strap so there’s no way that can stand straight up in their mouth and hurt him… The way that it works is that it’s a balance bit. So if you hang this on your finger, and you have it sitting on a horse, it’s at about a 45 degree angle if everything’s hanging right. It’s balanced in a way that it’ll always fall back to that spot. So a horse over time will shape his bridle, shape himself at the poll, to be in that neutral position where he feels no pressure at all. Over time he’ll start to bridle up and learn that, that’s why this process takes so long, he needs to develop his carriage, and he needs to learn how to bridle… The idea is to maintain the horse’s feet. And so this style of riding was developed to keep the life in your horse’s feet. He is now responsible for his carriage, he’s responsible for where he puts his feet, because if you’ve ever ridden outside much and had to do much work outside, the minute you pull a horse, and you put his feet somewhere, you have lost his heart. And at the end of the day you will be peddling this horse home. Because you micromanaged his feet in a way where he didn’t get to decide. Outside, he has to be responsible. You set things up so he can decide if he’s gonna turn that cow back, and he has to adjust himself to maintain in this footing. He has to be able to maintain in all different sorts of landscape, footings, so that he stays safe and sound. If you start to pull him, if you start to make him, you will have a crippled horse at the end of the day. Because he won’t want to try. Every time you have to move his feet, you lose a little bit of try. The reason that we use these tools is that we want the same horse we left with in the morning.’
It’s interesting how this is essentially the opposite of what Clint says. He’s all about ‘move his feet, move his feet!’ as a means of establishing control, and micromanaging the horse until they have no try left, only responses. The spade obviously exerts pressure and teaches a horse to move in a certain way, but it moves them in a way that’s physically beneficial (flex at the poll, collect the hocks under you, raise the back) and allows them to maintain that beneficial posture without the rider having to intervene, allowing them to remain sounder for longer.