The behind-the-scenes tales of hit products and creations from Japan: this is Japan's Top Inventions. This time, we feature erasable pens, which allow users to erase their writing just like with pencil. Released in 2006, these pens' usefulness has made them a hit: over 2 billion have been sold in some 100 countries and regions around the world. Discover the unknown story of these erasable pens, whose creation was inspired by the changing leaves of autumn.