A short video demonstrating Kajima corporation's new floor-by-floor demolition technique.
From Gridskipper.com: "First they replace the support pillars at ground level with computer-controlled metal columns. Then, a crew carefully demolishes by hand the entire floor, leaving the structure resting on the mechanic pillars, which then go down slowly until the next floor is at ground level. They replace again the support pillars with the mechanic ones, destroy that floor, and repeat the operation until they get rid of all the floors. This makes it look as if the building is shrinking in front of you, or being swallowed by the street.
"According to the company, this method greatly reduces the environmental impact of the demolition, as well as the time. Kajima says that it speeds up the task by 20%, while making it easier to separate materials for recycling, as well as reducing the amount of products released into the air.
The process is called daruma-otoshi after a japanese game that makes players take the bottom parts of a column—using a hammer—without disturbing the rest of the parts above."