So if you'll excuse me, I have a soapbox to get out now....
Now before I go on my rant, let me begin with a disclaimer. Yes, "pressure points" do exist. The human body does contain many places were the nerve(s) are relatively close to the top of the skin and applying force or pressure to these spots can create pain and discomfort.
However, their practical application is limited.
These "pressure points" (I really don't care for the term in general), are more easily manipulated in a close quarters grappling situation than in a striking situation. For a brief example, if you're in the process of applying an standing armbar on someone, instead of trying to hyper-extend the elbow, it does not take much effort to exert force on the other person's tricep tendon to elicit a painful response. However, if the opponent is struggling to get free, the application of such "pressure points" becomes significantly harder.
That is about the extent I will give pressure points in a practical application.
Now when it comes to trying to utilize pressure points in a striking situation, you are probably better off just playing the lottery. We all know that certain spots on the human body - sternum, temple, instep, testicles, etc - make for nice targets if you can hit them, but there is nothing about those spots that make them inherently a quote-unquote pressure point.
Most "pressure points instructors" will teach you an extensive list of points, often assigning them particular body organs (Liver, Heart, Large Intestine, etc) similar to that of the traditional Chinese medicine teachings. And the majority of these spots are only a few centimeters in size. Disregarding the notion that I have seen some instructors swear by the fact you have to hit certain pressure points in certain orders to be effective, the notion of trying to target an area a few centimeter large on a moving resisting target is mind boggling.
Now this brings us to the "well I saw it work on in a seminar/on YouTube/my cousin's backyard barbecue."
Yeah, but answer this question; if they are so effective, why haven't we seen even one successful application of a pressure point strike or (multiple strikes) in a MMA fight?
You know why? The person having the "pressure point knockout" done to them is completely compliant. Absolutely zero resistance. It doesn't take much effort to hit a target that doesn't move.
You know what else, practically every one of these demonstrations, ends with a strike to the side of the neck underneath the ear. Yeah, that's a good spot to hit if you have the chance. And it has nothing to do with pressure points. Why? Because you have a bunch of nerves that run down your neck in that location that control sensory and motor function. Don't believe me? Take a finger or two and press on the side of your head below your earlobe, right where your jaw ends. Now imagine someone striking that.
"But they're not striking it, they're just touching it"
Sorry, but that is just absolute unadulterated crap. Observe any "demonstration" with a watchful eye. The instructor may say they're only going to touch, but odds are they will be delivering a quick and semi-powerful strike. Now they may not being using their full force, but they certainly are not giving their uke a tap with the finger.
And don't even get me started on the whole "you have to strike wrist, then their forearm, then their head to disrupt their energy" mumbo jumbo.
I could go on, but I don't feel like writing a dissertation tonight.
And as if that wasn't bad enough, there are outright charlatans in the martial arts world who claim they can throw or project Chi/Ki energy. I'm not going to dignify these frauds by listing them or their organizations on this website (at least not at this time, we'll see what the future brings), if anyone cares for examples, contact me and I will gladly provide a plethora of examples.
The great thing about these frauds is that when they make too big of a name for themselves, they are usually called out about their crap. A Japanese master of the no-touch knockout accepted a sparring challenge and his "technique" was met with a fist in the mouth. A " Kung-Fu psychic" was outright debunked on national TV. One guy, after his no-touch failed to work on MMA fighters, claimed it only worked about 40% of the general population - despite ALWAYS working on his students - and that with trained athletes it rarely works. And probably the biggest name in the "no-touch knockout" BS explain why his techniques didn't work on a non-believer scientist? Well it could be a number of things. The scientist could have held his tongue to the roof of his mouth during the technique or possible had one big toe pointing up and one pointing down, which would nullify the energy. So basically if you want to attack this guy, just make sure your tongue is touching the roof of your mouth and you'll be fine.
In fact, there is only one name you need to know about the psychic/chi/ki bunk - James Randi. Randi is a long time skeptic of the paranormal and supernatural and has a long history of debunking frauds. His foundation has a long running open challenge - $1,000,000 to anyone who can show evidence under supervision and scrutiny of paranormal, occult, or supernatural abilities. It has yet to be awarded.
And while I'm sure all these no-touch "masters" are not in it for the money *snickers* a cool million dollars would be a nice retirement savings.
So in conclusion there are two things you need to know about pressure points & chi/ki. First, Chi/Ki/Whatever You Want To Call It doesn't exist. If someone does claim to teach no-touch/chi/ki stuff, you already know they're full of it. Second, pressure points do exist but are highly impractical. Want to learn pressure points just in case? I would advise you adopt the same philosophy I've adopted when it comes to striking pressure points - If you hit somewhere hard enough, it becomes a pressure point.
Now if you'll excuse me, I heard there is this new no-touch knockout system available in case you're attacked by farm animals and is being by none other than George Clooney himself!