It’s a legal punch, and can take the breath away from the boxer who takes it. It’s not the easiest punch to land, but a good liver shot, or many, will be very effective at weakening an opponent.
The liver is the largest internal organ, located in the right side of abdomen and although most of it is protected behind the rib cage, the lower part is not.
A well placed punch to this area, such as a left hook with an upwards angle, can be devastating and has ended many fights, and shortened many others.
Boxing Unboxed 