into exile in his holding at Sawayama Castle in the spring of 1599. Soon after, Maeda Toshiie died in April, and Toshinaga was elected to replace him; however, Ieyasu himself took up guardianship of Hideyori, occupying Ōsaka Castle on 28 October and further enraging the commissioners and council. Mobilisation Uesugi Kagekatsu, another councilman, defied Ieyasu by militarising, ordering 80,000 men to construct a castle in Aizu and expand its fortifications and road networks. On 7 May 1600, Ieyasu dispatched a letter to Kagekatsu demanding an explanation, Kagekatsu's chief advisor, Naoe Kanetsugu responded with mocking refusal. Subsequent negotiations broke down, with Kagekatsu even attempting to have one of Ieyasu's envoys killed as a spy, and after Kagekatsu refused to present in person at Ōsaka to account for his actions, Ieyasu summoned a war council on 12 July to plan a punitive expedition. On 24 July, Ieyasu departed from Ōsaka Castle for his punitive campaign, stopping at Fushimi Castle the next night to give his retainer Torii Mototada instructions against a likely Ishida-backed assault before continuing towards Aizu. Ieyasu was wary of a sudden attack by Mitsunari and his allies, and so he marched at a slow pace to monitor his rivals' movements, arriving in Edo on 10 August where he began mustering troops. Date Masamune and his uncle Mogami Yoshiaki, rulers of Sendai and Yamagata respectively on the border with the Uesugi clan's territory, returned swiftly to their home provinces to defend against Kagekatsu. Mitsunari immediately began summoning conspirators to Sawayama Castle following Ieyasu's departure, some even being convinced to abandon their journeys to join Ieyasu's campaign such as Ōtani Yoshitsugu. On 17 August Mitsunari's war council resolved to form the Western Army as a coalition against Ieyasu, with councilman Mōri Terumoto as its nominal commander-in-chief. On 22 August 1600, the coalition entered Ōsaka Castle and proclaimed the creation of the Western Army, claiming guardianship of Hideyori. The same day, Mitsunari issued a series of 13 charges against Ieyasu on behalf of the Five Commissioners and three members of the Council of Five Regents. This proclamation effectively marked the declaration of war between the Western and Eastern armies. Chūbu-Kansai theatre Engagements around Kyoto The first major assault of the Western Army in the region of the capital was the siege of Fushimi Castle commencing 27 August. Torii Mototada was resolved to defend the garrison to the last, and despite setbacks the