Kakurenbo (aka 「カクレンボ」). Japanese Theatrical Release April 23rd 2005.

Not seen this talked about anywhere else, it's 'Kakurenbo' from a new company called Yamato Works. Admitedly it's only a 25 minute short film, but it is getting a theatrical release soon in Japan, and it does look like a beautiful piece of work.

Yamato Works Official Site, which happens be dual language (see it here) explains the title effectively means "hide and seek" and explores folk tales from Japans' history. If you click on "Trailer" at that site you download the 15meg Quicktime trailer (or right click and save this) and see some pictures too.

There is also a large(ish) version of the poster to see here. Visit the distributors' site too. Finally, if I am right, it is associated with Manga Zoo who seem to do a lot of high quality short movies such as "Voices of A Distant Star" for example.