The final phase of Japan's Sengoku civil wars, in which Oda Nobunaga and his successor Toyotomi Hideyoshi militarily reunified the country after Nobunaga entered Kyoto in 1568 and dissolved the Ashikaga shogunate in 1573; Hideyoshi completed the unification and launched the failed invasions of Korea before his death in 1598.
Ended with Tokugawa Ieyasu's decisive victory over the Toyotomi loyalist coalition at the Battle of Sekigahara in 1600 CE, which unofficially established Tokugawa supremacy and led to the founding of the Tokugawa shogunate.
Dedicated English-language scholarly biography/reassessment of Oda Nobunaga, whose 1568 entry into Kyoto opens this period; verified on Open Library (title + author match).