Chi blocking is unique variation of the Dim Mak technique created by Ranma. Blocking someone's chi temporarily disables their ability to utilize it and at advanced stages renders the victim's muscles useless.
The breaking point of an object isn't an actual, physical point. It is a metaphorical point that can only be seen with the minds eye. Though Ranma did not go through the training he was there when Cologne explained the concept and by Ryoga using it so much he was able to tech himself the basics. What Ryoga first mistook as breaking points on Ranma’s body were actually key points in Ranma’s chi flows; places where several of the meridians crossed or joined together essentially pressure points. The Bakusai Tenketsu doesn’t have any effect on something with such a malleable chi flow. Which is why it didn’t work on Ranma. However Ranma has something that Ryoga doesn’t a rudimentary knowledge of shiatsu. This is why in addition to its secondary benefits many Amazon’s learn the Bakusai Tenketsu to aid them in their Shiatsu training.
Chi blocking is utilized by hitting these meridians with quick jabs and punches, and focusing a tiny amount of chi into them. The technique must be done rapidly, often giving little time for the recipient to react. User hit those meridians with relatively light jabs using her fingers and knuckles. Even people wearing strong, but not necessarily heavy, armor are not spared from its effects. Any fingers can be used, even the thumb. Ranma has also trained to utilize his feet to disable others' chi flow with a swing of his foot.
In Dim mak a few pounds of force is applied with expert precision to the right meridian points this coupled with a slow build up of chi causes a various effects. It is a lethal attack, painful and sudden. Chi blocking however combines this with various shiatsu techniques allowing user to stops their victims' chi flow, reduces their muscular strength, and temporarily disables their ability to utilize chi. The strength of the technique is proportional to the user’s shiatsu knowledge. Someone with only rudimentary knowledge can only disable someone’s abilities while a more advanced student can render muscles useless. A shiatsu master can do some real damage. This also allows the user to control the damage done. i.e they can either disable someone’s abilities, render muscles useless or both. Skilled users can also cause the loss of movement in various parts of the body. They don’t lose the ability to utilize their chi, but instead lose voluntary muscular function within a region localized around the attack, essentially becoming paralyzed. This was a similar effect to the paralyzing blocks; except it occurred slower and they only become paralyzed in the places struck. The technique has been described as a feeling of all the joints going soft, "like they're made of melted wax", and one felt "more flexible than you ever thought possible" the moment the chi blocking effect wore off completely.