Toyotomi Hideyoshi was a powerful medieval warlord and the bridge between two unifiers, successfully striving to unify Japan during a time of great unrest.

He was born on March 27, 1537, in Owari province. Ruling Japan at the time (often in name only) were the Ashikaga shogunate, a series of shogun who had intended to continue the trend toward military rule established during the Kamakura shogunate but instead lost control amid more than a century of civil war known as the Onin War and then the Sengoku ("Warring States") period.

Unlike many other warlords, Hideyoshi was born to peasant parents. In fact, his father was a foot soldier to a samurai. When that father died in 1543, Hideyoshi resolved to follow in his father's footsteps and, rather than join a temple, seek adventure. He became a foot soldier just like his father, first to a local ruler and then, in a stroke of fortune, to the powerful Oda Nobunaga, who in the 1550s was embarking on a campaign to unify Japan–under his own rule, of course.

Hideyoshi proved an invaluable servant, pitching in to repair castles, building forts, and discovering secret pathways into enemy territory. He also found ways to get Nobunaga's enemies to switch sides.

Hideyoshi was a more than able warrior as well, and Nobunaga put him in charge of a fighting force in 1570. His success in that realm gained him further trust, and Nobunaga named his protege daimyo of a handful of northern districts after a victory over the rival Asakura-Azai alliance, in 1573. His star ever ascending, Hideyoshi returned to the battlefield, leading Nobunaga's forces to victories in the next several years.

When Nobunaga died in the Honno-ji incident, in 1582, Hideyoshi assumed the mantle of leader and sought revenge for his captain's death, killing the traitor who had caused it. He was victorious over the Mori clan at the Battle of Yamazaki and declared himself Nobunaga's successor. He won the support of the Oda clan and from them formed a council of advisors. One of those, Shibata Katsuie, switched allegiances to one of Nobunaga's sons, Nobutaka, and declared himself in opposition to Hideyoshi's ascendancy. Katsuie was no much for the most powerful fighter in the land, and Hideyoshi emerged victorious, in the process claiming ownership of nearly three dozen provinces.

Hideyoshi also followed in Nobunaga's footsteps in forming an alliance with Tokugawa Ieyasu, after a brief struggle against each other. This allowed Hideyoshi to continue his unification campaign, which he did, assuming control of more provinces and then invading and conquering Shikoku Island, in 1585. Returning to Kyushu, he defeated the traditionally powerful Hojo clan in the Odawara campaign, besieging and eventually capturing Odawara Castle.

Hideyoshi's long campaign to rule all of Japan ended in 1591, after he put down the Kunohe rebellion. The following year, he took the title of Taiko, which was technically more highly placed in the hierarchy than shogun was.

To further his ambitions, he launched an invasion of Korea (which at the time was known as Joseon or Koryu). He was not nearly as successful in this endeavor, however. After initial victories, the Japanese forces encountered fierce resistance in the form of reinforcements from China. One particularly bitter defeat left Hideyoshi's force without a navy, meaning no sustained way of resupplying the invading army. They had the capacity to return to Japan and did so.