Originally called Neck & Neck, the 16mm cartoon was tagged with the name Mickey Manga Spide (Mickey Cartoon Speedy), and remained in Mr Watanabe's personal collection for 70 years.
The cartoon, titled "Empty Socks", was the first Christmas film made by the United States entertainment giant and was discovered during an inventory at the library's facility near the Arctic Circle.
The 16mm copy of "Neck "n" Neck" was in the possession of anime historian Yasushi Watanabe, who purchased the cartoon for about $4.40 when he was in high school nearly 70 years ago.
The significance of the film only became apparent when he read the book, Oswald the Lucky Rabbit: The Search for the Lost Disney Cartoons, written by long-term Disney animator David Bossert and published previous year.
It features a character, Oswald the Lucky Rabbit, who, in the two-minute consumer version owned by the researcher, is chased by a dog traffic cop while on a date. Watanabe, who is now 84 years old, bought the film at a toy wholesaler near his home in Osaka.
He never thought anything of it until recently, when he read the book Oswald the Lucky Rabbit: The Search for the Lost Disney Cartoons, by Disney animator David Bossert.
When Watanabe purchased the film, it cost him around $4.40.
The discovery was reported by Japan's Asahi Shimbun daily, which Watanabe contacted after reading a book about the history of "Oswald the Lucky Rabbit", the character Disney created in the 1920s. Of course, it's almost priceless now.
The original runtime of "Neck "n" Neck" was five minutes, but it was cut down to two minutes for the 16mm release.
"As I've been a Disney fan for many years, I'm happy that I was able to play a role", he told Asahi Shimbun.After speaking with Watanabe, the paper reached out to the Walt Disney Archives and confirmed that it was one of seven of the 26 Oswald cartoons that had been thought to be lost for good. Producer Charlez Mintz ended up taking Oswald to Universal, which in turn led to the creation of Mickey.
In 2006, Disney CEO Bob Iger made a trade with NBC Universal and regained control of the Oswald character.