Tsubasa & xxxholic crosses over, so if you read both of the mangas you can see the story from different perspectives. But you don't have to read both of them to understand.
This is what animenewsnetwork says about tsubasa:
Plot Summary: Sakura and Syaoran from Cardcaptor Sakura are back, but they aren't alone. CLAMP's brought together characters from all their creations for this alternate universe tale about the story of Syaoran, a boy who must travel across worlds with the help of Fye, a magician fleeing his own world, Kurogane, a ninja trying to get back to his own world, and Mokona, a creature given to them them by XXXHolic’s Yuuko, to help on their journey. Together they search for feathers of Sakura's memory in order to save her life.
This is what I think of tsubasa:
For me, tsubasa is one of my favorite mangas. That is because it has a lot of humor, & still has a good plot. & all the characters are the ones you love, from other clamp mangas. I recomend this manga if you haven't gotten into it allready. At least if you like other clamp mangas. I can't wait for the next volume to be released!
A community for tsubasa: tsubasarc
& then: XXXHOLIC
This is what animenewsnetwork says about xxxholic:
Plot Summary: Yuuko is a witch who grants people's wishes, but in return the person has to give up something precious. Watanuki Kimihiro, a man who has visions, encounters Yuuko and she promises to get rid of the spirits that torment him. In return Watanuki must work in Yuuko's shop and help her grant other people's wishes.
This is what I think of xxxholic:
This is a very good manga, although I don't like it as much as I like tsubasa. It has a lot of humor, but can be a little spooky at times with all the spirits & other beings that turn up in the story. & it's a good buy!
A community for xxxholic: xxx_holic
If any of you have read tsubasa or xxxholic or both, what do you think?