The behind-the-scenes tales of hit products and creations from Japan: this is Japan's Top Inventions. This time, a product used in over 20 countries and regions: stay-tight fasteners, nuts used with bolts in railroads, bridges, towers, and more. When normal nuts experience vibration, they sometimes come loose. But stay-tight fasteners, developed in Japan in 1974, overcame this problem. Learn the dramatic story behind the nuts, including a surprising spot that inspired their creation: a shrine!