Most Martial Artists today, when introduced to this information, say they already know it and their style uses pressure points. This is mostly true as almost all styles have "Pressure Points" in them for compliance and a few even striking (Atemi - dazing the opponent for easier additional technique application).
But this is not Kyusho.
The confusing thing in all related applications of weak targets (Atemi, Kupso, Dim Mak, Dian Xue, Kyusho, etc.) is that most believe they are all the same thing. While it is true they all share various qualities, this is not a qualifying aspect to label them all the same or equal.
Atemi - Atemi can be delivered by any part of the body to any part of the opponent's body. They can be percussive or use "soft" power. Karate is a typical martial art focusing on percussive atemi. Use of "pressure points" for pain compliance or stunning, as set up for a flowing technique of the style may be used.
Kupso- “Vital spot in Taekwon-Do is defined as any sensitive or breakable area on the body vulnerable to an attack. It is essential that the student of Taekwon-Do has a knowledge of the different spots so that he can use the proper attacking or blocking tool. Indiscriminate attack is to be condemned as it is inefficient and wasteful of energy”. – General Choi Hong Hi (최홍희), ENCYCLOPEDIA OF TAEKWON-DO, Volume II, page 88.
Acupuncture/pressure - A method of relieving pain or curing illness by pressing on particular points on a person's body with the fingertips or thumbs. A model based ontraditional Chinese medicine bodywork technique based on the principles of acupuncture. Acupressure is the application of pressure rather than needles on specific points on the body to control symptoms such as pain or nausea. Another way to understand this by definition; Chinese term for points in the skin through which wind may flow.
Dim Mak / Dian Xue - The Cantonese term dim mak does not translate to “death touch” the less dramatic, but more accurate translation would be “press artery”. By definition, dim mak operates on arteries, which are continuous and span the entire body. Yes, some pressure points happen to be located along these arteries. No, this does not make dim mak synonymous with pressure point striking or grappling.
Kyusho - Translates as Vital Spot, or a weaker anatomical structure... this is not associated with acupuncture as it relates to the underlying anatomical structures, in modern application it is more centered on the nerves (see: http://www.kyusho.com/dim-mak-vs-kyusho/ ). From the large pool of notes, scrolls and writings of bygone generations of masters of the art, we can clearly ascertain these Kyusho targets are not pressure points but rather more generalized areas.
Keep in mind all these are simplistic definitions, but they do serve the purpose of separating the basis and that they are not all the same. They work on different principles, methods and especially targets.. by starting with this base (definition), we can then better see what direction we want to take in our studies.
We need to get out of the fog and into the defining principles of each method as opposed to lumping them all into a single category. Only then can we develop our true potential as well as higher degree of skill.