If you are doing the horse stance, doesn't it just expose you to groin kicks? Also, if you want to block the groin kick, you could lift your knee and block it but the horse stance makes it slower as the legs are spread apart. So why do people use the horse stance if it is just going to leave them exposed for groin shots?
The question asks why horse stances exist in martial arts in general.
The horse stance gets a lot of bad press. Lots of people just make fun of it, saying that it leaves people vulnerable to kicks to the groin as well as being pushed over. So why do a horse stance?
Well, why do any stances? What is the purpose of stances in general?
There are many stances you'll see in different forms-based martial arts such as kung-fu, karate, and Taekwondo. Each stance in a form is kind of like a snapshot in time of some self-defense application. It's best to see a stance merely as a position that's in the middle of some transition going on. That way, you won't get too hung up in the idea that a stance is "fixed" and static. All stances are dynamic.
With regards to the horse stance, again people laugh at this, but you can see a horse stance in Judo and Brazilian Jiujitsu all the time. Nobody makes fun of it or points it out then, do they?
When you do a hip throw (O-Goshi Nage in Judo), for example, you have to do a horse stance. You step towards your opponent, reach around his back, turn your back so that it's now against his front, and then lift him onto your back and throw him over your hip. In doing so, that stance you're in is a horse stance. That's the optimal stance for that particular throw.
The horse stance that's typically done in modern Japanese karate and Taekwondo is very elongated. But the root of both of those styles is Okinawan karate, where the horse stance is quite high and narrow. The high and narrow version of the horse stance is probably a closer approximation of what you'll actually perform in real life self-defense. The reason it's elongated in Japanese karate is to emphasize physical conditioning. It's simply harder to do and builds more muscle.
Most of what you see in forms (karate, Taekwondo, kung fu, etc.) is self-defense. It's not teaching you how to spar. That would be ridiculous. You don't learn to block punches and kicks by doing forms. You learn that from sparring. Instead, forms were meant to be done with partners and teach self-defense techniques.
You can learn more about this subject at my answer in the following link:
In sparring or free-fighting, you would never stand in a horse stance facing your opponent. That would make no sense other than to maybe decoy him into attacking your groin.
But the horse stance makes perfect sense in real world stand-up grappling applications, like the ones I mentioned in the link above.
I've heard others explain that it's actually fairly strong when used from side-to-side. If you push on someone while he's in a horse stance, it's easy to push him over if you push on his front, but you can't budge him if you push against his side. So some people explain that the side-to-side position can be used in sparring or free-fighting. While that is somewhat true, most people don't actually fight in a horse stance like that. So it's really hard to make the claim that this was its original intent. It almost never is the case when you see it done in forms.
There are plenty of self-defense scenarios that you might encounter where you're basically in a horse stance. Most of the time out in the real world just enjoying yourself, you're going to be standing in a perfectly neutral, upright stance like normal. Then let's say someone comes up behind you and gets you in a bear hug. All you do to make a horse stance is to step out a little bit (not a lot), dropping your weight a bit, and bending at the knees. It's an instinctive response. People do it even without any martial arts training whatsoever. You're lowering your center of gravity and making it harder to be thrown.
The karate kata "naihanchi" specializes in the horse stance and these sorts of scenarios. It has nothing to do with free-fighting. It's all about self-defense against these common everyday scenarios you find yourself in. It's as valid today as it was 100+ years ago when it was created.
Bottom line, don't use the horse stance in sparring or free-fighting. Do use it in stand-up grappling. But don't focus on the stance. Focus on the self-defense technique. The stance is just what happens in between movements. It's just a snapshot in time.
Hope that helps.
If you are doing the horse stance, doesn't it just expose you to groin kicks?
So why do people use the horse stance if it is just going to leave them exposed for groin shots?
The purpose of the horse stance is not for fighting, but for training. You use the horse stance during training to develop leg strength, hip flexibility, and body structure. This is similar to how might you use push ups or squats to get stronger, even though they may not directly applicable to fighting.