Reservoir Chronicle (ツバサ-RESERVoir CHRoNiCLE- Tsubasa: Rezaboa Kuronikuru) is a shōnen manga series written and illustrated by the manga artist group Clamp. It takes place in the same fictional universe as many of Clamp's other manga series, most notably xxxHolic. The plot follows how Sakura, the princess of the Kingdom of Clow, loses her soul and how Syaoran, a young archaeologist who is her childhood friend, goes on a quest to save her. Dimensional Witch Yūko Ichihara instructs him to go with two people, Kurogane and Fai D. Flowright. They search for Sakura's memories, which were scattered in various worlds in the form as feathers, as gathering them will help save her soul. Tsubasa was conceived when four Clamp artists wanted to create a manga series that connected all their previous works. They took the designs for the main protagonists from their earlier manga called Cardcaptor Sakura.
It was serialized in the Kodansha publication Weekly Shōnen Magazine from May 2003 until October 2009, and was collected in twenty-eight tankōbon volumes. The manga was adapted into an anime series, Tsubasa Chronicle (ツバサ･クロニクル Tsubasa Kuronikuru?), animated by Bee Train, which aired 52 episodes over two seasons during 2005 and 2006. Production I.G released an interlude film between the first two seasons titled The Princess in the Birdcage Kingdom, as well as five original video animations (OVAs) between November 2007 and May 2009, which acted as a sequel to the second season. Various video games and drama based on the series have been released. The manga was licensed for English language release by Del Rey Manga, who has released all of its volumes since April 27, 2004. Funimation Entertainment licensed the anime for English release. They published all the TV episodes in volumes as well as the film. The OVAs of Tsubasa were released in North America in January 2011.
The series has been well received by Japanese and English readers, and it reached high positions on various best-seller lists; the series has sold over twenty million manga volumes in Japan as of September 2009. Both the manga and anime have had positive response from critics, who praised its connections to previous works and its artwork. The plot twists in later parts of the story have been generally praised for how they affect the overall plot as well as for being surprising. However, they have been criticized for being confusing.