One of the most memorable case studies I came across with as I studied Japanese management at Sophia University in Tokyo was the case of the empty soap box, which happened in one of Japan's biggest cosmetics companies.
The company received a complaint that a consumer had bought a box of soap that was empty. It immediately isolated the problem to the assembly line, which transported all the packaged boxes of soap to the delivery department. For some reason, one soap box went through the assembly line empty. Management tasked its engineers to solve the problem.

