How did the death of Imagawa Yoshimoto change Tokugawa Ieyasu’s position?

The death of Imagawa Yoshimoto in 1560, following his defeat by Oda Nobunaga, served as a pivotal turning point for Tokugawa Ieyasu. Having spent his youth as a hostage of the Imagawa clan, Ieyasu seized the opportunity created by Yoshimoto's demise to break free from their control.123

Ieyasu returned to his ancestral lands to assume command of his surviving relatives and vassals. He quickly moved to secure his position by allying himself with the rising power of Nobunaga, while simultaneously pacifying the new, less capable leadership of the Imagawa house to retrieve his wife and son from Sumpu. This shift allowed Ieyasu to transition from a subordinate role under the Imagawa to an independent leader, enabling him to focus on internal consolidation, such as crushing rebellious Buddhist sects and improving his domain's administrative and military infrastructure. This newfound autonomy laid the foundation for his eventual rise as a major daimyo and his later role as the unifier of Japan.12