Luke Skywalker Turned A Sith Technique To His Advantage When He Redeemed Darth Vader

A useful lightsaber combat technique typically used by the Sith Lords was also used by Luke Skywalker against Darth Vader in Return of the Jedi.

https://screenrant.com/return-of-the-jedi-luke-skywalker-darth-vader-redeemed-sith-technique/