Punching the nose will hurt the brain, and punching the eyes will also hurt the brain. Hitting the back of the head will damage the brain stem and lead to rapid death. There is also a fatal position on the back neck, which will be fatal if you press it hard (the specific position is difficult to explain)

Punching the ribs, throat, vest and genitals can also cause great harm, but it doesn't necessarily kill you.

Many other positions can also be killed by a powerful blow, but they are not mentioned because they are too important.