There are alot of Japanese games that are completely unknown to the rest of the world. Games like Jesus or Misty Blue are all but forgotten for anyone not doing active preservation. That's where the game preservation comes in, and they've got their work cut out for them.
Because, it's becoming harder and harder to obtain these obscure software titles, even more so a working one. The race is on to preserve these before it's too late. Read more on their fanscinating work here
Keep preserving rare titles! Games are an art-form afterall!