How can you tell a first printing of Rayearth?
Rayearth is a kind series to authenticate, because its original editions are few and exactly documented. In Japan there is one first edition to look for: Kodansha’s Nakayoshi tankōbon of 1994 to 1996, six volumes whose release dates and ISBNs are a matter of record, listed in full in the manga gallery. A Japanese set matching that table is the first edition; anything else is a reprint or a different edition, however similar the covers.
In English the tell is physical. Tokyopop’s first collected edition (1999–2001) is flipped: it reads left-to-right, and its second series is numbered as volumes 4 to 6. The 2003–04 re-release reads right-to-left and restores the numbering. Reading direction and the spine number identify an American Rayearth faster than any other mark on the book.