Board Thread:General Discussion/@comment-4957813-20131130185522/@comment-11444045-20140919122529

Better question is: why would Ryuken even make the charm to begin with?

Ryuken doesn't even like Soul Reapers or isn't even that friendly to Kisuke or Isshin(sometimes). While i'm not denying he could be able to it just seems dumb to interfere with situations that has nothing to do with Quincy's or himself. Urahara is a prime suspect on who would make a device like that because he's the genius of the manga. His intellect far surpasses anyone on the manga/show even to Aizen who admits he's smarter than him.

Considering the fact Urahara gave Rukia Kon to begin with i think it would make more sense for him to make a charm for kon while he's using Ichigo's body while Ichigo off doing his soul reaping thing. I'm going to say it's kido based and created by Kisuke following the events when Isshin realized Kon entered Ichigo's body and the flashback where he's smoking by Masaki's grave, he probably told Urahara after Ichigo and Co went to save Rukia in the soul society. Thus why at episode 63(or 64) Isshin told ichigo to hold onto the charm. Made no sense for Ryuken to get involved with Soul Reaper Mod Soul business. Hell he doesn't even care for his duties as a Quincy as he told Uryu many times which made him dislike his father. See after watching the anime many times you come to realize things(sure not 100% accurate but for the important canon parts) about the people. ;)

If ryuken made the device he would have personally gave it to Ichigo who he never appeared until the beginning of the arrancar arc.