I'm constantly trying to reconcile martial arts with practical self defence. Sometimes in doing so, I feel very much out of my depth. Ie really struggle to see anything practical in certain aspects of a style. Sometimes it's blatantly obvious of course, sometimes it's there but less obvious, and sometimes, try as I might, I can't see it for looking.
One example is the head up, guard down stances of karate, taekwondo, and some styles of kung fu. I've heard the argument that it's best to guard the torso because nobody can repeatedly strike the hard head without damaging their own hands, but I completely don't buy that whatsoever. I've witnessed enough violence to know that people will break their own hands on people's skulls and keep going. Even if your average beer fuelled thug was to say 'ooh, that hurt my knuckles, I won't do it again', the person whose head they broke their knuckles on is in a worse position.
So why do we practice stances with our head so exposed and our guard low?
The only possible tenuous connection to self defence I can think of is that the best defence is often apparent confidence, and keeping your head up and unguarded signals confidence. I wouldn't bet money on that being effective either.
Reasins I've heard include, it keeps your airways open. But boxers are among the fittest athletes there is, and they keep their chin down and guard up. Head up means you can more easily see multiple attackers. Maybe. But then there's more attackers to hit your unguarded head. And unless I'm unique, peripheral vision works very well with chin down and guard up too. Head up makes you look more like a psycho and therefore more intimidating. But if you're under attack, you're not the psycho. That title goes to the other guy.
I'm sure there's a reason. I just can't see it.