After Luke lost his lightsaber in the cloud city, he built a new lightsaber. For this, he needed kyber crystals. Rogue One: A Star Wars Story movie shows that Empire was controlling kyber crystal reservoirs. While stealing a box of kyber crystals from Empire goons shouldn't be difficult, I am concerned about a ritual in which younglings find crystals hidden behind mysteries (a Star Wars: The Clone Wars episode and the Ahsoka book are on my mind). The problem is , there seems to be no specific description of where Luke got the kyber crystal from in the current Star Wars canon, other than that he was missing the "right pieces" needed for the construction of a lightsaber and found those parts (possibly including the crystal) amongst Ben's possessions on Tatooine. It makes sense for Ben to have had a lightsaber spare parts given that he was expecting to be there for a considerable amount of time and, critically, would have wanted Luke to construct his own saber at the end of his training. This is also makes sense considering Ben had left his Journal or diary for Luke in his home on Tatooine(Star Wars Issue 15- From the Journal of Obi-Wan Kenobi). Ben knew Luke would return to his home planet for the Journal, maybe he had left extra lightsaber parts there as well and Luke eventually returned to recover them? [quote]And yet he seemed to know exactly what he needed to know. [b]Reaching out with his mind, he found the right pieces—some easily purchased, some much harder to acquire.[/b] [b]After leaving Obi-Wan’s hut, he knew he had at last collected everything he needed. [/b]While our other heroes bustled about preparing for the rescue, Luke retreated into the solitude of a desert cave and puzzled over the pieces….In the end it took not just physical tools but also the Force to put it all together and bring the crystal inside to life. Return of the Jedi: Beware the Power of the Dark Side! [/quote] There's also mention in Heir to the Jedi that Luke was able to salvage a working lightsaber that belonged to a former Jedi. This included a kyber crystal and several focusing crystals. [quote]“All right, I understand. Just a moment.” I collected the pieces of Huulik’s lightsaber and placed them in a small bag. “Come on, Artoo,” I said. “We have to run and hide again.” Star Wars: Heir to the Jedi[/quote] There is no defining evidence in the Canon that details how Luke obtained his lightsaber in [i]Return of the Jedi[/i], only hints. But I conclude this: Luke eventually was either was instructed or told by the Force to return to Ben's home. Here, Ben had left extra lightsaber parts similes to how he left the Journal for Luke, Luke then combined those parts with the parts from Huulik’s lightsaber to form his own. That is my theory on the construction of Luke's lightsaber in [i]Return to the Jedi[/i]. If you have anything to add or argue, I encourage it. Have a wonderful morning everyone.