Japanese military history spans centuries, beginning with the formation of the samurai class in the late 12th century. The samurai were skilled warriors who served powerful feudal lords, known as daimyōs, and played a crucial role in the unification of Japan during the Sengoku period. This era saw the rise of notable figures like Oda Nobunaga and Toyotomi Hideyoshi, who helped consolidate power and establish a centralized government. In the late 19th and early 20th centuries, Japan underwent rapid modernization, transforming its military into a formidable force. This led to victories in conflicts such as the First Sino-Japanese War and the Russo-Japanese War, establishing Japan as a major world power. However, Japan's militarism escalated during World War II, resulting in significant conflict and eventual defeat in 1945, which reshaped its military and political landscape in the post-war