From the pages of Wasyu's Encyclopedia Tenchicca--
Unlike film comics, manga usually contain original works.
The Tenchi Muyo! Ryo-oh-ki manga by manga artist Okuda Hitoshi, is loosely based on the first OVA series. The original Japanese edition is published by Kadokawa Shoten Publishing; the North American translation and publishing is done by Viz Comics; the Mandarin translation and publishing is done by Tohan Corporation.
For more information on the Tenchi Muyo! manga, please refer to Tenchi Muyo!: Data Bank.