The Sengoku Period in Japan existed from c. 1467-1603. This time was the time of political intrigue and constant warfare. Japan at that time was spread out as many independent kingdoms, vying for power. There was no unification. Tokugawa Ieyasu changed all that.
Ieyasu was born in 1543, and lived a dangerous childhood, surrounded by war. By 1565, Ieyasu had allied with Oda Nobunaga, a powerful warlord with the dream of uniting Japan under his rule. Ieyasu was also very powerful, and had many vassals at this point. Ieyasu conquered even more territory, but he then learned that Nobunaga had been assassinated in 1582. Ieyasu conquered Nobunaga’s former provinces, but there was a new powerful warlord: Toyotomi Hideyoshi. Hideyoshi fought against Ieyasu before the two powerful warlords became allies. In 1590, the last independent warlord was defeated, and Hideyoshi and Ieyasu jointly ruled Japan. However, Hideyoshi died in 1598, and his heir, Toyotomi Hideyori, was young-only five years old.
Ieyasu gained allies and in 1600 engaged Hideyori’s forces, led by the powerful regents of the kingdom and the supporters of Hideyoshi. The Tokugawa Clan was the victor of the final battle, the famous battle of Sekigahara. Hideyori committed suicide, and Ieyasu proclaimed himself the first Shogun of Japan. He would be very powerful until his death in 1616.