Battle of Baekgang
In East Asia, Tang Chinese military campaigns were less successful elsewhere than in previous imperial Chinese dynasties. Like the emperors of the Sui dynasty before him, Taizong established a military campaign in 644 against the Korean kingdom of Goguryeo in the Goguryeo–Tang War; however, this led to its withdrawal in the first campaign because they failed to overcome the successful defense led by General Yeon Gaesomun. Allying with the Korean Silla Kingdom, the Chinese fought against Baekje and their Yamato Japanese allies in the Battle of Baekgang in August 663, a decisive Tang–Silla victory. The Tang dynasty navy had several different ship types at its disposal to engage in naval warfare, these ships described by Li Quan in his "Taipai Yinjing" (Canon of the White and Gloomy Planet of War) of 759. The Battle of Baekgang was actually a restoration movement by remnant forces of Baekje, since their kingdom was toppled in 660 by a joint Tang–Silla invasion, led by Chinese general Su Dingfang and Korean general Kim Yushin (595–673). In another joint invasion with Silla, the Tang army severely weakened the Goguryeo Kingdom in the north by taking out its outer forts in the year 645. With joint attacks by Silla and Tang armies under commander Li Shiji (594–669), the Kingdom of Goguryeo was destroyed by 668.