Divided into two stages (Winter Campaign and Summer Campaign), lasting from 1614 to 1615, the siege put an end to the last major armed opposition to the shogunate’s establishment. The Siege of Osaka Castle was a series of battles undertaken by the Tokugawa shogunate against the Toyotomi clan, and ending in that clan’s destruction. The other theory is the opposite where they planned a safety net Masayuki, Yukimura, and Nobuyuki discussed the situation when Ieyasu asked them to state their allegiance clearly, and they decided to join separate sides, so that, regardless of the outcome of the battle, the Sanada clan would survive. The true motive of Masayuki and Yukimura's decision is disputed with many theories, but there are two main schools of thought: in one, Masayuki made the decision (and Yukimura agreed) he expressed the willingness to take a gamble, so that if he were to join the weak side and win the battle, the Sanada would gain much more power. It has been said that at first Yukimura followed Ieyasu but, after Ieyasu tried to seize his territory he betrayed Ieyasu. The Sanada clan complied as well, but when Ishida Mitsunari decided to challenge Ieyasu, Masayuki and Yukimura joined the western forces, parting ways with Masayuki's eldest son and Yukimura's brother, Nobuyuki, who joined the eastern forces. In 1600, before the Battle of Sekigahara, Tokugawa Ieyasu rallied various daimyōs to attack Uesugi Kagekatsu. Eventually, the Sanada clan became a vassal of Toyotomi Hideyoshi. The Sanada initially surrendered to Oda Nobunaga, but, after the incident at Honnō-ji, it became independent again, drifting between stronger daimyōs such as the Uesugi clan, the Later Hōjō clan, and the Tokugawa clan. īy 1582, the Oda- Tokugawa forces had destroyed the Takeda clan. Yukimura also went, taking the Sanada name as well. Masayuki, previously serving Takeda Shingen and Takeda Katsuyori as a retainer, inherited the Sanada clan and left for Ueda Castle. In 1575, the Battle of Nagashino claimed the lives of two of Sanada Masayuki's elder brothers.

Three other wives of Yukimura were his first wife the daughter/sister of Hotta Sakubei, who lost her status to Chikurin-in Takanashi Naiki's daughter and Ryūsei-in (a daughter of Toyotomi Hidetsugu). He was married to Chikurin-in (Akihime), Ōtani Yoshitsugu's daughter and adopted daughter of Toyotomi Hideyoshi.

He was the second son of Sanada Masayuki (1547–1611). 3.2 Summer Siege of Osaka Castle and Death.

Yukimura sanada ikemen sengoku