This became one of the most financially successful Japanese films ever made. Its deeply-felt pacifism, director Hayao Miyazaki has said, was inspired by his outrage over the United States war in Iraq.
The original release date was July 17, 2004, but production delays forced this to be moved back.
Premiered in September 2004 at the Venice Film Festival.
The English-language version debuted in select North American theaters on June 10, 2005, with wider distribution one week later.
British author Diana Wynne Jones said that "Howl's Moving Castle" is "a very visual book. I think it appealed to Miyazaki because it was about magic in four or five places at once."
She also believes that her characters will have attracted Miyazaki's imagination. "I imagine that Miyazaki might, almost at once, have set about thinking how to draw and animate a fire demon [Calcifer]. I can't wait to see how he's done. I have heard he's not being done as simple animated fire, but that's all I know."
According to Miyazaki's studio, the director liked the book's idea of a young girl being transformed into an elderly lady. Reportedly, Miyazaki had difficulty figuring out how to make his elderly heroine attractive.
Reflected Jones: "I discovered, writing the book, that old women are much funnier than young girls. I hope Miyazaki has noticed this, too. Turning the heroine into an old woman may not have been done before, but I always wondered why not. People are more than a little hidebound."
Jones said she had minimal contact with Miyazaki's studio. "My one real contact was when a group of studio people visited me, with interpreters. The group was trying to establish a proper visual background for the film."
Jones was dubious about having the studio set the film in Wales. "I tried hard to dissuade them from going to Cardiff, and suggested that a smaller Welsh town would be better. They seemed not to understand the nature of the moorland where Howl's castle is (most of the time), or what a fishing village looked like. I suggested examples, which was difficult as I had largely made these places up, but they seemed doubtful about going there."
The film's setting is actually modeled on the French region of Alsace, but Jones is not concerned by the changes that Miyazaki has made to her book: "I have been an admirer of Miyazaki for many years. He has an ability to make beautiful, meticulous images without ever losing the rhythm and impetus of his story. It isn't really my place to have fears and reservations."