The poster not only teases a big struggle for the Straw Hats, but reveals the film will be opening August 9 in Japan.
20周年夏の新たなる冒険、続報をお待ちください！ pic.twitter.com/G6nunw2Uoq— ONE PIECE.com(ワンピース) (@OPcom_info) December 11, 2018
Now officially titled One Piece: Stampede, the film was first reported on earlier this year as a celebration of the anime first going into production in 1999. Much of the details about the film have been kept under wraps, but it was previously reported that the film would take place after the events of One Piece Film: Z and One Piece Film: Gold. There are currently no details as to how much original creator Eiichiro Oda will be involved with the project, if at all as well.
The poster for the film teases a major metal kaiju or mechanoid creature that's hastily pulled together. Along with seeing pieces of junk coming together to form the creature, Luffy's famous Straw Hat is blowing in the wind. This could tease a major loss for the Straw Hats, but at this point it's more of a tease as to how intense the new film will be. Regardless of what this creature actually is, it does have a massive scale and may be something special to watch on screen.
There is currently no confirmation as to the canonicity of the new film either, but most of the One Piece films take place outside of the usual canon anyway. It could very well be the same situation here for this film as well, but it would add an impressive layer of scale should it integrated into the series officially.
Eiichiro Oda's One Piece first began serialization in Shueisha's Weekly Shonen Jump in 1997. It has since been collected into over 80 volumes, and has been a critical and commercial success worldwide with many of the volumes breaking printing records in Japan. The manga has even set a Guinness World Record for the most copies published for the same comic book by a single author, and is the best-selling manga series worldwide with over 430 million copies sold. The series still ranked number one in manga sales in 2018, which surprised fans of major new entries.