Dun Möch was a form of combat that used distraction and doubt, usually through taunting, in conjunction with lightsaber combat.
The Sith aimed to completely dominate an opponent’s spirit through whatever means possible by employing their own lightsaber combat doctrine. Dun Möch commonly involved spoken taunts, jeers, and jests that exposed the opponent’s hidden, inner weaknesses or doubts, which had the end result of eroding the opponent’s will. Mental attacks would also be utilized during combat in order to strip one’s concentration with the Force, making an opponent less precise and effective. Such a thing could be quite deadly, especially against Jedi, since concentration was of vital importance when using the Force. As such, Dun Möch embodied using the Force as a form of psychological warfare.
Correctly executing Dun Möch required great patience, a rare trait of the Sith during the time of the Brotherhood of Darkness. This need for patience was exhibited by Darth Bane during his duel with the Zabrak Sirak during a combat training session at the Sith academy on Korriban. He exhibited patience by drawing out the battle and demoralized his opponent by withholding the final blow and capitalizing on his mistakes. Instead he allowed the tantalizing closeness of Sirak’s defeat fuel his vengeance before unleashing it with a strong enough blow to disarm him and end the duel. Lightsaber combat instructor and Blademaster Kas’im commended Bane’s use of Dun Möch and declared it a valuable lesson to all of the other students at the conclusion of the fight.
The most successful practitioners of Dun Möch were the ones that took the practice to the level of plotting. Desann used Dun Möch by faking the death of Jan Ors and taunting Kyle Katarn about his powerlessness, tricking the enraged Katarn to reveal the location of the Valley of the Jedi. Darth Traya lied to Colonel Tobin (who was working for Darth Nihilus at the time) about a supposed Jedi Academy on Telos IV. Nihilus took the bait, which left him vulnerable to Meetra Surik, who killed him. Darth Sidious, arguably the greatest practitioner, would plan events that would take years, if not decades, to come to fruition. The Clone Wars could be considered an extreme usage of Dun Möch by Sidious, in order to distract the Jedi Order to allow him to wipe them all out quickly with Order 66. Aside from this, he also used a rather extreme version of Dun Möch during his duel with Yoda in the Senate, where he proceeded to hurl several repulsorpods at Yoda, constantly forcing Yoda to dodge until Yoda turned the tables on him by redirecting a repulsorpod back at him, forcing Sidious to dodge.
However, a common misconception is that Dun Möch was only used by Sith. Like Force lightning, Dun Möch could also be employed by Jedi in certain circumstances. It is theorized by some that this may have occurred during the confrontation between Darth Sion and Meetra Surik on Malachor V, though this use did not match the standard usage of Dun Möch and was completely different from any seen before. Sion was indestructible by conventional methods, as he was capable of healing his wounds in an instant. Surik instead used taunts and arguments to erode Sion’s will, which in the end caused Sion to sacrifice his own life to the Force.
However, most applications of the technique by Jedi had the more benign goal of motivating opponents to surrender, as shown by Obi-Wan Kenobi’s taunts of Asajj Ventress during their duel on Teth, though again, this may not have actually been Dun Möch.