Why Did Both The Jedi And Sith Hate This Lightsaber Variant?

The flicker phase blade. It ignites and extinguishes at random intervals, so an opponent can never reliably block it and can never force a saberlock, and it leaves most duelists swinging at a weapon that is not there. The Jedi Order regarded it as dishonourable and unsporting, and it never saw widespread use. The Sith left it alone too, and the likely reason is that needing a trick to win is an admission of weakness. (Knights of Fate)

The galaxy had plenty of options#

There is nothing sacred about the single blade. Over the millennia the lightsaber has been built into every shape someone could think of. (Star Wars Rebels, "Spark of Rebellion"; Star Wars: Knights of the Old Republic)

The Inquisitors of the Galactic Empire carried spinning dual-bladed rings that doubled as flight units. Double-bladed saberstaffs were common enough among Dark Jedi and Sith Lords during the Jedi Civil War, and in Legends Darth Maul grew the four synthetic crystals for his own, spending four days in deep meditation while they formed. In Legends there are dual-phase lightsabers with extending blades, carried by the likes of Gantoris and Corran Horn. There is the Darksaber, stolen out of the Jedi Temple by Mandalorians millennia ago and handed down until it reached Pre Vizsla. (Star Wars Rebels, "Spark of Rebellion"; Star Wars: Knights of the Old Republic; Darth Maul: Shadow Hunter; Dark Apprentice; I, Jedi; The Clone Wars, "The Mandalore Plot"; Star Wars Rebels, "Trials of the Darksaber")

And there is the lightwhip, the strangest of the lot. A Legends weapon with a flexible blade several metres long, capable of attacking from angles no straight blade can reach, and able to overwhelm a defence from all sides when built with multiple tassels. It was also expensive, hard to control, prone to maiming its own wielder, and hard to use defensively, since a flexible strand is poor at parrying. (Legacy of the Force: Betrayal; Jedi Academy Training Manual; The Jedi Path: A Manual for Students of the Force)

Despite all of that variety, the overwhelming majority of both the Jedi Order and the Sith carried a single blade and nothing else. (Knights of Fate)

Two orders, one refusal, two reasons#

The Jedi position is the one on record: the Order saw the flicker phase blade as dishonourable and unsporting. The reasoning behind that is philosophical. A lightsaber that gives you an unfair advantage removes the need for perseverance, and perseverance was understood as part of walking the light side. The weapon was supposed to be a plain tool, with the difficulty carried by the person holding it. Buy your way past that difficulty and you have skipped the part that was meant to develop you. (Knights of Fate)

No source spells out a Sith position, but their own philosophy points the same way by a completely different road. To a Sith, reaching for a gimmick means you could not win without one, and weakness advertised in front of other Sith is how you end up replaced. Power was supposed to be personal. A blade that fights for you undercuts the whole point. (Knights of Fate)

Two orders that agreed on almost nothing agreed on this, which is what makes the exception interesting. (Knights of Fate)

The one they actually hated#

The flicker phase blade is not exotic in shape. It is a lightsaber whose blade cuts in and out at unpredictable intervals, and that single property breaks the fundamentals of lightsaber duelling. (Knights of Fate)

Blocking depends on the blade being there when you meet it. A saberlock depends on both blades staying lit long enough to press against each other. Reading an opponent depends on their weapon behaving consistently between exchanges. The flicker phase blade removes all three at once. Defenders find themselves parrying nothing, then getting hit by a blade that reignites mid-swing, then losing the read entirely because there is no rhythm to learn. (Knights of Fate)

The catch is that the wielder has to work with the same unpredictability the enemy is suffering from. It never saw widespread use. (Knights of Fate)

Trakata does the same job by hand#

The technique version of this idea exists and is well documented, and it is called Trakata. (Star Wars Roleplaying Game Saga Edition Core Rulebook)

In Legends, Trakata was developed by a Jedi Consular during the days of the Old Republic specifically to work around the weaknesses of using a lightsaber. It is built on shutting the blade off and reigniting it quickly, creating confusion and opening space for diversionary feints. Mixed with the two-blade style Jar'Kai it was described as extremely effective even against multiple opponents at once. (Star Wars Roleplaying Game Saga Edition Core Rulebook)

The named moves show exactly why people hated fighting it. Pass the Blade has the duelist deactivate their weapon mid-attack, sliding straight through the opponent's block, then reignite it inside a defence that is no longer there. Unbalancing Block has the duelist catch the enemy's blade, kill their own, and let the opponent stumble forward into an opening they created themselves. (Jedi Academy Training Manual)

It has killed people. Corran Horn used a version during the Yuuzhan Vong War against Shedao Shai on Ithor, deactivating his blade while the two were locked together and reigniting it into him. The Sith apprentice Tahiri Veila used it on Ben Skywalker in Legends, switching off and on fast enough to put a blade where his throat had been a moment earlier. (The New Jedi Order: Dark Tide II: Ruin; Legacy of the Force: Invincible)

Canon has picked it up too. The Sith known as the Stranger used Trakata against a group of Jedi on Khofar, then again in his rematch with Master Sol on Brendok. Sol used it back, well enough to destroy the Stranger's weapon and win. Cal Kestis used it briefly against the Second Sister on Bogano, and Marrok tried it on Ahsoka Tano in their final duel, though she recovered quickly enough to finish him anyway. (The Acolyte, "Night", "The Acolyte"; Star Wars Jedi: Fallen Order; Ahsoka, "Part Four: Fallen Jedi")

One footnote worth having. Trakata began life as a fan creation and was brought into continuity through the Star Wars Roleplaying Game Saga Edition Core Rulebook, which is a fairly unusual route into the lore for something now appearing in live action. (Star Wars Roleplaying Game Saga Edition Core Rulebook)

Why it never caught on#

The technique survives. The weapon does not, and the reason is cultural rather than practical. (Knights of Fate)

Both orders had a version of the same instinct: if you need the blade to do the thinking, you have not learned to fight. A Jedi who wins because their weapon confused someone has not built the discipline the Order cared about. A Sith who wins that way has shown every rival exactly how to beat them. So the flicker phase blade stayed a curiosity, hated by both sides for reasons that barely overlap, while the technique that mimics it kept quietly killing people for thousands of years. (Knights of Fate; The Acolyte, "The Acolyte")