a general withdrawal in the evening to the valley of Sekigahara after learning of Kobayakawa Hideaki's occupation of Mount Matsuo, emptying Ōgaki Castle of most of its garrison. On 21 October, the Western Army arrayed itself in the valley with Mitsunari's headquarters at the foot of Mount Sasao facing the Eastern Army, while Mōri Hidemoto led a separate formation at the Eastern Army's left flank at the foot of Mount Nangu. While both sides became aware of each others' positions at dawn, a thick fog halted plans initially and battle was not commenced until 8am when the fog cleared. The subsequent battle of Sekigahara saw a decisive defeat for the Western Army, with Mitsunari's contingent annihilated by Kobayakawa Hideaki defecting to the Eastern Army and rolling down the formation's right flank, while after a smaller engagement and the treachery of Kikkawa Hiroie forced the eastern formation under Mōri Hidemoto to withdraw rather than join battle. From 21 to 30 October, Ōgaki Castle was subsequently besieged and taken by the Eastern Army, while on 22 October Kobayakawa Hideaki began besieging Sawayama, ostensibly as a sign of penance and loyalty to Ieyasu; Ishida Masazumi, Mitsunari's brother and commander at Sawayama, capitulated and committed suicide on the second day of the siege. Ishida Mutsnari and Ankokuji Ekei were captured fleeing north from Sekigahara, and were subsequently executed in Kyoto on 9 November. Nakasendō campaign On 25 August, Ōtani Yoshitsugu had made contact with the Sanada clan at Ueda Castle and recruited Sanada Masayuki and his son Yukimura; the eldest son, Sanada Nobuyuki, had already been sent by Masayuki to join the Tokugawa, with whom he already had marriage ties through his wife Komatsuhime in an attempt to preserve the Sanada clan. After dispatching the Tōkaidō Corps, Ieyasu sent his son Tokugawa Hidetada along the Nakasendō road with 36,000 men towards Mino, ordering him to threaten Ueda Castle while continuing on to meet the Tōkaidō Corps. He reached Karuizawa on 7 October and subsequently arrived in Komoro on 12 October; however, there he disobeyed his father's orders and instead marched on Ueda, encaping at Sometani. Komatsuhime herself had a brief but bloodless confrontation at Numata Castle with Masayuki and Yukimura before the siege of Ueda began in earnest. Hidetada, being unexperienced in warfare at 21 years old, besieged Ueda Castle and its commander Sanada Masayuki unsuccessfully until 16 October, at which point he realised