User blog comment:Lia Schiffer/416: Deicide 18 (The End)/@comment-1432572-20100821153156/@comment-1454424-20100821163234

I don't know what it says about me since that I seem to be one of the few people who can follow Kubo's convoluted timeline but allow my to explain.

Aizen did not get his hands on Urahara's hogyoku until the events of the Soul Society Arc. The flashback was of him looking-up information in the Great Library. We know that he conducted research on... Urahara's research while he pretended to be dead but was actually holding up in Central 46 compound. So... the Hogyoku Gin saw Aizen with as a child was the one Aizen came-up with. He clearly spent years offering it sprite energy to try and "satisfy it" but it wasn't please. So finally, he went after Urahara's Hogyoku. Which, while incomplete, was clearly still more powerful then Aizen's since Urahara's one turned the hollowfication of Shinji and co into Vizardification (without the Hogyoku, they would have simply turned into full hollows) and granted Orihime and Chad their desires by awakening for them, their own powers.

However, when Aizen did his research on Urahara's research during the Soul Society Arc, he found that as powerful as Urahara's Hogyoku is, it is still incomplete. So from what I can tell, he then took his "evil" Hogyoku that demanded blood sacrifice (in a manner of speaking) and Urahara's Hogyoku which went around granting wishes, even not so good wishes like Rukia losing all her power due to her guilt over Kaien's death and merged them into a Shikono-tama one single Hogyoku.

I hope that makes sense... I am sleepy...