As the battle grew more intense, the Takamatsu garrison received reinforcements from Mōri Terumoto, who brought an army two times larger than Hideyoshi's.

Adopting this tactic, Hideyoshi immediately started building an embankment, under the direction of Kuroda Yoshitaka, with support from Hachisuka Masakatsu, Ukita Tadaie, Horio Yoshiharu, Ikoma Chikamasa, Kuwayama Shigeharu, and Toda Masaharu.

[4] On June 8, which happened to be in the rainy season, the long-lasting rain swelled the Ashimori river, developing a lake and rendered Takamatsu Castle a solitary island.

Later, Shimizu Muneharu, the castle's commander, was forced to commit suicide in a boat on the artificial lake created by the flooding, in full view of both sides.

[5] The siege is described and dramatized in the novel Taiko: An Epic Novel of War and Glory in Feudal Japan, written by Eiji Yoshikawa and translated to English by William Scott Wilson.