Board Thread:Manga/@comment-35417358-20161009053634/@comment-5774380-20161009214045

It's funny that you mention them because I never agreed with the designation of the first 3 arcs.

The latest 3 arcs are chronological and consistent with the volume releases, but the first 3 arcs have no consistency whatsoever. First we have a mini-arc of 2 chapters, then the first chapter of the second arc, then a third arc of 13 chapters, and then the remaining 4 chapters of the second arc; and none of them following the volume releases (with chapter 18 even being part of two arcs).

The Spanish wiki considers volumes 1 and 2 (chapters 1 to 9) as part of an arc called the "Introductory arc", and volumes 3 and 4 (chapters 10 to 18) as the "Transformation arc".

For my part, I consider volume 1 as a single introductory arc which starts and ends with the Colossus Titan (his first appearance in 845 and his return in 850), and all of the other chapters up until the Female Titan arc (5 to 18, or volumes 2 to 4) as part of the Battle of Trost.