B'Arq's defense is a defensive maneuver in bat'leth combat, considered to be nearly impenetrable. Worf was able to devise a method for penetrating the defense, which led to his victory in a bat'leth tournament in 2370. He was later able to devise a similar countermove, using a mek'leth rather than a bat'leth, which he first employed against his ambassadorial aide, Giancarlo Wu, in early 2376. (TNG novel: Diplomatic Implausibility)

Spock, following a mind meld with Worf, was also able to penetrate B'Arq's defense in battle against a Klingon thrall of Malkus the Mighty. (TNG - The Brave and the Bold, Book Two novella: The Final Artifact)