Extrait du site (Wookieepedia):
Alchaka was an extremely personal ritual performed during meditation by members of the Je'daii Order and later the Jedi Order.
History
Developed by the early Je'daii Masters of the Stav Kesh academy on the Deep Core planet Tython, the Alchaka meditations were a highly personalized meditative technique that brought practitioners to the brink of exhaustion and closer still to the Force. At the time, members of the Je'daii Order would often joke that the meditations were invented to keep warm, as Stav Kesh was located high in the snow-capped mountain ranges of the planet.
Over the centuries, the Je'daii left Tython and relocated to the Outer Rim planet Ossus where they renamed themselves the Jedi Order. The technique of Alchaka was passed down from generation to generation, surviving longer than any of the academies it was taught at. Nearly twenty five thousand years after it was created, Alchaka was still taught at the Coruscant Jedi Temple. Jedi High Council member Obi-Wan Kenobi took the meditations very seriously, becoming slightly upset when Alderaanian Senator Bail Organa witnessed his practicing while aboard the ship ferrying them to Zigoola on a vital Jedi assignment.