The behind-the-scenes tales of hit products and creations from Japan: this is Japan's Top Inventions. This time, quartz wristwatches, which caused a "timepiece revolution" with their accurate timing. Built in Japan in 1969, the world's first quartz wristwatch drifted only 0.2 seconds a day, making it about 100 times more accurate than previous watches. Even now, 96% of watches around the world use the same system. We trace the drama behind the creation of this super-accurate timepiece.