雁门关
Yang Ye, a general of the Northern Han Kingdom, was nicknamed "Invincible" (無敵) due to his tactical prowess and unmatched gallantry in battle. He served the Song Dynasty after Liu Jiyuan, ruler of Northern Han, surrendered. Emperor Taizong of Song had great faith in Yang Ye and commissioned him to defend Song's northern border from the Khitan-ruled Liao Dynasty, which Yang Ye proved himself by defeating in the Battle of Yanmen Pass, instilling fear in the enemy but also incurring jealousy of some Song officials.