This appears to be two trailers — one short and one long — for a Toei Company animated feature from 1963 called Wanpaku Ouji no Orochi Taiji (literally “The Naughty Prince Slays the Giant Serpent”) — released in English as The Little Prince and the Eight-Headed Dragon.

The movie is available undubbed in eleven pieces on YouTube, and though the story is legible even to the non-Japanese speaker, I believe I’ll need to find and procure this film legitimately for myself, if possible.

The animation and design are astonishing, particularly for Japan in 1963. Simple, clean lines lend economy of form to appealing and believable characters; the motion, though simple, is subtle and nuanced. The absolute believability of masses during rotations and deformities is as sure and solid as rotoscoped shapes. The color design and backgrounds are generally gorgeous, and the layouts and staging are all very clear and forthright.

The director of animation, Yasuji Mori, was also an illustrator of children’s books; three years later he was working as an animator on another Toei feature, Gulliver’s Travels Beyond the Moon. The film didn’t have a satisfactory ending, but a 25-year-old inbetweener named Hayao Miyazaki suggested a better one, which was used. This brought Miyazaki notice within Toei, and started him on the path to directing.

Miyazaki’s work clearly exhibits much of the directorial philosophy of these early Toei pictures, including a clear-eyed and ingenuous sentimentality and the inclusion of actual peril for contrast.