The user is able to deal attacks to the weak points in their enemy dealing double the damage or causing very lethal pain or fatal wounds. Highly advanced users can take down their opponent in one attack.
Exploit weaknesses in your opponents armor or shields
One swift attack can damage an enemy's vital organs
...to deliver a critical blow to Nappa, breaking his back and permanently crippling him.
Son Goku (Dragon Ball) uses Miracle Blow to punch through Broly's stomach, reopening his childhood wound and dealing a critical blow onto him, physically and mentally.
During his fight Cell, Gohan (Dragon Ball series) in his Super Saiyan 2 was able to deliver a powerful kick to his body, not only greatly injuring Cell, but also have him eventually regurgitate Android 18 and revert back to his Semi-Perfect form.
Son Gohan (Dragon Ball) use his Quiet Rage to punch right through Bojack's stomach, dealing a critical blow.
Oboro (Gintama) infusing his ki into his Hakkei strike to deal a critical blow to Gintoki's meridian.
Terra's (Kingdom Hearts) entire fighting style is centered around this ability.
Kain (Legacy of Kain) deals a single critical strike to an opponent by using the Fury Dark Gift.
With his 100% power, Younger Toguro (Yu Yu Hakusho) was able to deliver a critical blow to Yusuke's arm and leave him writhing in pain.