I've previously blogged on the Dark Horse animated version, a couple of times.
12. Was your online comic "Tsuru " (Dark Horse Comics) reprinted anywhere? Are there any other stories where origami is a theme?
(WWW Board July 2000) The story was first published in monthly installments in The Dark Horse Extra, a monthly advertising tabloid newsletter. It will be reprinted in an upcoming trade paperback collection.
The short story "Tsuru" [Which you can find on the UY Animation page], which was serialized in Dark Horse Extra, has an assassin with a habit of folding paper cranes [reprinted in UY Book 14 "Demon Mask"]. Also the story "Runaways" [UY Vol 3, #13-14 and UY Book 9] takes place during the Tanabata Festival one of whose customs is trimming branches with paper cranes and other paraphenalia. I don't offhand recall any other stories.
One footnote to the Tsuru story is that I had intended to include instructions on folding cranes however I wound up needing the space for story. Maybe I'll include it next time when the opportunity arises.
(WWW Board Apr 2000) The story, Tsuru (crane), will be included in a forthcoming volume but in black & white. [It's in USAGI YOJIMBO Book 14: Demon Mask]
The first episode has Usagi entering a roadside inn where he notices a guy folding a paper crane.
He goes over and comments on it.
The guy says: "It helps me remember all those I've killed."
Usagi: "The crane is a symbol of long life. How many have you killed?"
Guy: "More than you can count. I am an assassin."
To be continued.