Oda Nobunaga was a Japanese daimyō and one of the leading figures of the Sengoku and Azuchi-Momoyama periods. He was the Tenka-bito and regarded as the first "Great Unifier" of Japan. N…Oda Nobunaga was a Japanese daimyō and one of the leading figures of the Sengoku and Azuchi-Momoyama periods. He was the Tenka-bito and regarded as the first "Great Unifier" of Japan. Nobunaga was an influential figure in Japanese history and is regarded as one of the three great unifiers of Japan, along with his retainers Toyotomi Hideyoshi and Tokugawa Ieyasu. The period when Nobunaga and Toyotomi Hideyoshi were in power is called the Azuchi-Momoyama period. The name "Azuchi-Momoyama" comes from the fact that Nobunaga's castle, Azuchi Castle, was located in Azuchi, Shiga, and Fushimi Castle, where Hideyoshi lived after his retirement, was located in Momoyama.