Force-bond

"Master Yoda has come to Moraband, although why, I do not know. We shall, however, use the strong bond that once existed between you and your master to allow us to see things that we otherwise could not."

- Darth Sidious, to Count Dooku

A Force-bond was a strong connection in the Force between two Force-sensitive beings. These Force-bonds could be created through a Jedi Master and their Padawan.

During the Clone Wars, the Dark Lords of the Sith&mdash;Darth Sidious and Darth Tyranus&mdash;took advantage of Tyranus' Force-bond to his former Jedi Master, Yoda, in order to reach the Jedi Master from across the galaxy. While on Coruscant, the two Sith Lords were able to sense that Yoda was on Moraband&mdash;the ancient Sith homeworld&mdash;and used Tyranus' former bond with his Master to enact a dark side ritual to summon the power of dark illusion to try and break the Jedi Master's will. They ultimately failed.