How can you tell a first printing of Attack on Titan?
Japanese collected volumes carry a colophon (the okuzuke) on the final pages, and it states the printing plainly: the publication date and the impression number, conventionally read as “first edition, first printing” followed by the date that impression was issued. A first-printing copy of Attack on Titan volume 1 shows the impression line dated at the book’s launch window, March 2010; a later impression of the same volume shows a later date with the same ISBN.
Supporting evidence sits around the colophon rather than in it: an intact obi (the paper band around the dust jacket, printed with the launch campaign copy) and, on limited editions, the correct bundled extras for that volume’s ISBN. Two cautions govern the whole shelf. ISBN alone proves nothing, since impressions share it; and a volume’s printing line must be checked in hand or from a photograph of the colophon page, not from a listing’s title. Sellers who photograph the okuzuke are telling you they know what they have.