For "Once Upon a Time in the West", Leone changed his approach over his earlier Westerns. Whereas the ""Dollars"" films were quirky and up-tempo, a celebratory yet tongue-in-cheek parody of the icons of the Wild West, this film is much slower in pace and somber in theme. Leone's distinctive style, which is very different from, but very much influenced by, Akira Kurosawa's "Sanshiro Sugata" (1943), is still present, but has been modified for the beginning of Leone's second trilogy, the so-called "Once Upon a Time" trilogy. The characters in this film are also beginning to change markedly over their predecessors in the "Dollars" trilogy. They are not quite as defined, and unusual for Leone characters up to this point, they begin to change (or at least attempt to) over the course of the story. This signals the start of the second phase of Leone's style, which was further developed in "Duck, You Sucker!" and "Once Upon a Time in America".