The 1973 OPEC oil embargo and resulting economic shock provided the definitive real-world validation of TPS. While Western automakers — burdened with massive inventories, inflexible production lines, and gas-guzzling product lineups — suffered prolonged losses, toyota-motor-corporation recovered faster than any competitor. TPS's lean inventory (just-in-time), flexible production (heijunka, smed), and built-in quality (jidoka) proved to be exactly the capabilities needed in a volatile, resource-constrained environment. Japanese competitors took notice: the oil crisis made other Japanese manufacturers study and adopt TPS methods, beginning TPS's spread beyond Toyota. This event transformed TPS from an internal Toyota experiment into a proven competitive advantage, setting the stage for the Western discovery that would follow.