As you may well know, the Honda Motor Company was founded by Soichiro Honda in 1946 in Hamamatsu, Japan. Even before the Second World War Soichiro Honda had run a business manufacturing piston rings. Honda is now a huge global corporation making motorcycles, cars and all manner of devices driven by internal combustion engines.
In 2003 Honda developed a radical downhill mountainbike called the Honda RN01, and tested it on the domestic Japanese downhill racing circuit. The Honda RN01 featured a mysterious and, supposedly, highly secret 'gearbox' surrounding the bottom bracket. Inside this gearbox was a fairly straightforward derailleur system, using a custom designed, but surprisingly conventional, derailleur.
In 2004 Honda set up a full-blown world-class downhill mountainbike racing team called Team G Cross Honda. Honda hired the reigning World Champion, Greg Minnaar to head up the team. Team G Cross Honda rode the Honda RN01 - and although they did not sweep all before them, they were moderately successful with it.
I believe that the Honda 'gearbox' evolved through a number of iterations (perhaps three), before Honda disbanded the team at the end of the 2007 season.