What Was the First Naruto Movie, Ninja Clash in the Land of Snow?
The premise is pure early Naruto. Kakashi's team is hired to guard the actress Yukie Fujikaze during a film shoot in the Land of Snow, and she proves to be Koyuki Kazahana, the exiled heir of that country, whose uncle Doto seized power with chakra armor technology and a hunt for her crystal necklace. The film folds the mission structure of the Wave arc into a bigger canvas: snow trains, an airship, armor-clad enemy ninja and a finale powered by a geothermal generator and the famous rainbow chakra moment.
Production context explains its look. Pierrot made the film as the television series' first theatrical expansion, with the television staff and cast, and its budget shows in set pieces television could not attempt in 2004, particularly the train and airship sequences. It opened at number one in Japan in its release window and established the commercial rhythm of a Naruto film each summer, a slot the franchise held for a decade.
Its place in continuity is the standard film answer: it fits loosely after the early television arcs, contradicts nothing important, and is never referenced by the manga. The films of this era were built as parallel summer adventures, and the Library documents them as their own shelf rather than forcing them into the chapter timeline.
For collectors, the Snow film's artifacts are era pieces: Japanese theatrical programs and posters, the first film's DVD editions in both markets, and the novelization and film comic versions on the Japanese shelf. As the first film, it is the anchor of a movie collection in the same way volume 1 anchors the manga run.

Film facts
Japanese release: August 2004. Studio: Pierrot. Story: Team 7 escorts actress and hidden princess Koyuki in the Land of Snow. Position: first of eleven theatrical films; self-contained from the manga.
Collector note
Theatrical programs are the signature Japanese artifact for the film line; the Snow program begins the set. English theatrical exposure came later and briefly, so US materials are thinner than the Japanese record.
