He fought with the Western Army during the Battle of Sekigahara in 1600, defending the inner bailey of Sawayama-jo Castle with Masazumi, but under Hideaki KOBAYAMA's furious attacks, the castle fell within half a day and Masatsugu committed suicide with his sword.
1600（慶長5）年関ヶ原の戦いでは西軍に与し、正澄とともに佐和山城にいて本丸を守備するも、小早川秀秋らの猛攻に遭って半日も持たずに敗退、落城に際して正継は自刃した。