In the 1585 invasion of Shikoku, Toyotomi Hideyoshi

Toyotomi Hideyoshi

was a daimyo warrior, general and politician of the Sengoku period. He unified the political factions of Japan. He succeeded his former liege lord, Oda Nobunaga, and brought an end to the Sengoku period. The period of his rule is often called the Momoyama period, named after Hideyoshi's castle...

 seized Shikoku

Shikoku

is the smallest and least populous of the four main islands of Japan, located south of Honshū and east of the island of Kyūshū. Its ancient names include Iyo-no-futana-shima , Iyo-shima , and Futana-shima...

, the smallest of Japan's four main islands, from Chōsokabe Motochika

Chosokabe Motochika

was a Sengoku period daimyo in Japan. He was the 21st chief of the Chōsokabe clan of Tosa Province . He was the son and heir of Chōsokabe Kunichika and his mother was a daughter of the Saitō clan of Mino Province....

.

Hideyoshi's army was divided into three forces. The first, under Hashiba Hidenaga and Hashiba Hidetsugu, consisted of 60,000 men, and assaulted the provinces of Awa

Awa Province (Tokushima)

was an old province of Japan in the area that is today a part of Tokushima Prefecture on Shikoku. Awa was bordered by Tosa, Sanuki, and Iyo Provinces. It was sometimes called .-References:...

 and Tosa

Tosa Province

is the name of a former province of Japan in the area that is today Kōchi Prefecture on Shikoku. Tosa was bordered by Iyo and Awa Provinces. It was sometimes called .-History:The ancient capital was near modern Nankoku...

, approaching Shikoku via Akashi island

Akashi, Hyogo

is a city located in southern Hyōgo Prefecture, Japan, on the Seto Inland Sea west of Kobe.As of April 1, 2011, the city has an estimated population of 290,776, with 117,392 households, and a population density of 5,907.68 persons per km²...

. The second force was led by Ukita Hideie

Ukita Hideie

was the daimyo of Bizen and Mimasaka provinces , and one of the council of Five Elders appointed by Toyotomi Hideyoshi. Son of Ukita Naoie, he married Gohime, a daughter of Maeda Toshiie...

, who led 23,000 men against Sanuki province

Sanuki Province

was an old province of Japan on the island of Shikoku, with the same boundaries as modern Kagawa Prefecture. It was sometimes called .It faced the Inland Sea and bordered on Awa and Iyo Provinces. Across Naruto strait it bordered Awaji Province too. Administratively it was included as a part of...

. The final attack force consisted of 30,000 men, and advanced on Iyo province

Iyo Province

was an old province of Japan in the area that is today Ehime Prefecture on Shikoku. Iyo bordered on Awa, Sanuki, and Tosa Provinces. It was sometimes called ....

, led by Mōri Terumoto

Mori Terumoto

Mōri Terumoto , son of Mōri Takamoto and grandson and successor of the great warlord Mōri Motonari, fought against Toyotomi Hideyoshi but was eventually overcome, participated in the Kyūshū campaign on Hideyoshi's side and built Hiroshima Castle, thus essentially founding Hiroshima.Terumoto was a...

, Kobayakawa Takakage

Kobayakawa Takakage

was a samurai retainer of Toyotomi Hideyoshi during Japan's Sengoku period, and the son of Mōri Motonari. Adopted by the head of the Kobayakawa clan, Takakage took his name, and succeeded his adoptive father to become head of the Kobayakawa clan following his death in 1545.As head of the Kobayakawa...

, and Kikkawa Motonaga. In total, it took 600 larger ships and 103 smaller ships to transport Hideyoshi's army to Shikoku.

Despite the overwhelming size of Hideyoshi's army, and the suggestions of his advisors, Chōsokabe chose to fight to defend his territories. The battles culminated in the siege of Ichinomiya Castle, which lasted for 26 days. Chōsokabe made a half-hearted attempt to relieve his castle from the siege, but surrendered in the end. He was allowed to keep Tosa province, while the rest of Shikoku was divided among Hideyoshi's generals.