It's a reference to the pre-World War II forerunners of a corporate form whose modern iterations are better known as keiretsu, those vertically integrated manufacturing and trading cartels that gave Japan Inc. its fearsome reputation in the 1980s.
An 18k white gold skeleton frame is designed as a complex set of gears, in reference to the 1936 film in which the Chaplin character struggles to survive in the modern, industrialized world.
For the modern horophile, perhaps the only thing more thrilling than wearing, say, a sought-after Patek Philippe Reference 1518 on one's wrist, is the honor of having another discriminating enthusiast take notice of the benchmark timepiece.