Video: Daruma-otoshi skyscraper demolition

From Pink Tentacle:

Japanese construction firm Kajima Corporation is using an innovative new skyscraper demolition method to dismantle a pair of old company buildings in Tokyo. (Watch a time-lapse video.) Unlike conventional demolition that begins at the top of the building, Kajima's new method starts at the bottom. As each floor is demolished, the support columns are cut and replaced with giant computer-controlled jacks, which slowly lower the entire building one floor at a time. The process is repeated for each successive floor until the entire building is gone. Kajima informally calls this the daruma-otoshi method, after the old Japanese game consisting of a daruma doll made of stacked pieces that players knock out one by one without toppling the doll. (Watch a super slo-mo video.) According to Kajima, the daruma-otoshi demolition method — which is now being used to dismantle a 75 meter (246 ft) tall, 20-story building and a 65 meter (213 ft) tall, 17-story building — is safer and creates less noise and dust pollution because the work is kept close to the ground. In addition, this method cuts demolition time by 20% and makes it easier to separate and recycle the building materials.

Watch the video