The short is not based on existing published material (anime, manga, manhwa etc.) - it must be an original work.
Experimental Shorts created by a non-professional who later works on professionally produced anime may be retroactively added.
Exceptions may be granted for student graduation projects from Japanese animation universities.
Rain Town Is an experimental short by Hiroyasu Ishida. At the time of creation, he was an independent non-professional animator. As he has now worked on professionally produced works such as Penguin Highway, this entry is acceptable.