BiographySakon Shima was born in Settsu Province in 1540, in Osaka Prefecture. He was a ronin, but found service in the Takeda Army of Shingen Takeda in 1558, fighting in the Sagami-Suruga Conflict, leading the Imagawa Army Vanguard. He fought again in the Battle of Kawanakajima with great impact; his mobile unit saved the day for the Takeda, Sakon leading all 10,000 troops in the Takeda mobile unit in an attack on the Uesugi rear after the Uesugi had defeated Shingen's main force, saving the day and winning the battle. Sakon Shima continued to serve Shingen, fighting at Mimase Pass, where he assisted Shingen by delivering provisions to the withdrawing soldiers. In 1572, he served at the Battle of Hitokotozaka, a pre-battle to the Battle of Mikatagahara, fighting Tokugawa warrior Tadakatsu Honda with aid from Yukimura Sanada. Tadakatsu lost most of his troops, but held off Sakon and Yukimura, who failed to take his head. He fought at Mikatagahara, and killed Tokugawa's kagemusha agents, and learned that strategy was only half the battle; resolve and loyalty also mattered. That was the last battle that he fought for the Takeda, as Shingen Takeda fell ill and passed away shortly after his greatest triumph.
Sakon Shima found service in the ranks of Hideyoshi Hashiba's army, the Toyotomi clan, and fought Ieyasu Tokugawa once more at the Battle of Komaki-Nagakute in 1584 in the Unification of Japan. Sakon took part in the Siege of Oshi Castle in 1590 as an aide-de-camp to Mitsunari Ishida, and took the castle, despite devastating losses. Sakon served overseas in Korea alongside the great warriors of Japan, including Yukinaga Konishi and Yoshitsugu Otani, two future allies. By the time he had returned from Korea in 1598, Hideyoshi's health was fading and he died shortly after the Korean adventure ended. Sakon enlisted in the Western Army, a group of Toyotomi loyalists led by Mitsunari that fought against the Eastern Army, troops led by Ieyasu, who assumed command of Hideyoshi's territories in Japan.As the official strategist for the Western Army, he had a lot on his plate; he had to deal with the wavering morale of the Western Army, who were uninspired by the lack of volunteers. He also had to deal with the recruitment of soldiers, many of whom were conscripted into the army after there was scant enthusiasm to join Mitsunari's troops, who were outmatched in numbers and in political and military power. In 1600, the year that the Sekigahara Campaign began, Sakon Shima would lead his first campaign.
He started off by ambushing the Tokugawa camp at the Kuze River, held by Tadakatsu Honda. The Battle of Kuzegawa, his most famous adventure, had begun. This was one of the opening acts of the Battle of Sekigahara, which was seeing only a few confused skirmishes; the Jinba Plains were covered in fog that obscured the battlefield and made movements improbable. Sakon Shima succeeded in testing the Tokugawa resolve, defeating Tadakatsu, but both sides suffered heavy losses, Sakon losing valued general Motochika Chosokabe. Sakon Shima's "victory" at Kuzegawa was overshadowed by the various defeats endured by the Western Army, and the failure to concentrate the war on one front; the Western Army's armies were scattered, with fighting raging as far south as Kyushu's northern provinces and as far north as Iwate Province in the northeastern corner of Honshu. Sakon Shima ordered several muskets to equip the Western Army, as well as European cannon; if the strength of numbers would not prevail, perhaps technology would?This idea was tested in the final confrontation at Sekigahara. Sakon's European great bombards did some damage on the Tokugawa, and Sakon's riflemen did even more damage. But as the fog blinded both sides, accuracy was discarded as it was impossible to aim in the thick fog. Nagamasa Kuroda's riflemen inflicted heavy losses on Sakon's force.
Shima, an excellent rifleman, wounded Naomasa Ii from a distance with one of his shots, so Assassin Order member Taka Yamauchi headed to show Sakon that he was just as vulnerable as his enemies. Yamauchi assassinated Sakon with his hidden blades, and Yamauchi comforted Shima, telling him that he did his part and his role in the story was over. Shima bade him farewell, before dying.