Sokan was a principle of lightsaber combat, rather than a true form.
Developed by the ancient Jedi Knights during the Great Hyperspace War, Sokan teaching revolved around using the environment itself to gain a tactical advantage in combat.[1]
Sokan involved maneuvering so that swift strokes of the lightsaber could be aimed toward the opponent's vital areas, using quick tumbles, jumps, and movements. Combatants made use of large amounts of terrain, trying to maneuver their opponents into vulnerable areas during the course of battles that involved Sokan techniques. This technique allowed for great speed and mobility and left no openings in one's defense. Prior to the Clone Wars, Sokan practitioners integrated highly kinetic elements of Ataru with their ancient Sokan techniques to create a blend of styles that relied upon agility. It was recommended for practitioners to use this style in their home ground or on familiar terrain.
[1]
Although it was unclear whether Obi-Wan Kenobi received formal Sokan training or not, the Jedi Master did employ elements of Sokan while duelingDarth Vader on Mustafar. Toward the end of the duel, Obi-Wan sought the high ground and used his favorable positioning to defeat Vader, attacking his weak points. This was the factor that led to Vader's defeat. However, the Sith Lord seemed to have learned his lesson from this defeat and was known to use saberthrow when his opponents gained the high ground rather than pursue them, like in his final duel with his son.[3][4]
In his brief duel with Count Dooku during the Battle of Geonosis, Master Yoda used a three-point leap around the hangar in which they were fighting to evade the Count's bladework and regain the initiative against him.