- "Imagine in your mind a fortress of stone and steel, with crenellated walls. Within it stands a keep, itself walled."
- ―Relin Druur, passing on to Marr Idi-Shael the technique of shielding oneself with the Force
This shielding technique was one of the first lessons taught by members of the Jedi Order to Force-sensitives. The technique involved using the Force to negate the effects of the dark side of the Force on one's mind by imagining an impenetrable fortress within one's mind. One application of the shielding technique was to negate the effects of the dark side felt by light side users when they were nearby powerful dark side objects such as Lignan ore. By 5,000 BBY, the technique was one of the most common skills that was taught to Jedi in the Jedi Order, and it had been passed down for many generations. Imar Deez taught this technique to Relin Druur, who in turn taught it to Drev Hassin and Marr Idi-Shael.