There's not much information yet about this short on the web other than its the brainchild of a Japanese comedian named Tekken (Takefumi Kurashina) and is titled Furiko, or Pendulum in English. I can't really confirm, but I think it is been released only recently this year.
Basically it follows the lifetime relationship of a couple. Its very similar to that immensely touching scene between Carl and Ellie in Up . That particular Pixar scene is called Married Life, and quite honestly one the best moments in cinematic history. Personally I don't think Pendulum is on the same level as Married Life (it very hard to achieve that status), but it still evokes a powerful emotional response from the audience.