Yang Liang (楊諒) – courtesy name Dezhang (德章), alternative name Jie (傑), nickname Yiqian (益錢) – was an imperial prince of the Chinese Sui Dynasty. He was a son of Emperor Wen and his powerful wife Empress Dugu, who, during his father's reign, controlled the region north of the Yellow River. After his father's death in 604, he rose against his brother Emperor Yang but was soon defeated by Emperor Yang's general Yang Su and forced to surrender. He was reduced to commoner rank and imprisoned for the rest of his life.
Background
It is not known exactly when Yang Liang was born, but it is known that he was the youngest of the five sons of Yang Jian and Yang Jian's wife Dugu Qieluo. As the third of his older brothers, Yang Jun, was born in 571 (the fourth, Yang Xiu, similarly has an unknown birth year) and he was already born at least by the time that Yang Jian seized the throne from Emperor Jing of Northern Zhou, ending Northern Zhou and establishing the Sui Dynasty as Emperor Wen in 581, he would have been born sometime between 573 and 580. In 581, after Emperor Wen took the throne, he created his sons imperial princes, and Yang Liang was created the Prince of Han.
During Emperor Wen's reign
Yang Liang did not participate in the campaign that destroyed rival Chen Dynasty in 589 and unified China (in which his older brothers Yang Guang the Prince of Jin and Yang Jun the Prince of Qin participated), suggesting that he was not yet old enough by that point. In 592, he was made the governor of the capital province Yong Province (雍州, roughly modern Xi'an, Shaanxi). In 597, he was made the commandant at Bing Province (并州, roughly modern Taiyuan, Shanxi), and was in charge of the 52 provinces north of the Yellow River. In 598, when Emperor Wen attacked Goguryeo, Yang Liang served as co-commander of the operation (along with the general Wang Shiji ()). The Sui forces later withdrew, Goguryeo then sued for peace. (During the campaign, the general Gao Jiong served as Yang Liang's lieutenant, and, due to his senior status, often disobeyed the young Yang Liang, causing Yang Liang to be so displeased that he complained to his mother Empress Dugu, further straining the relationship between Empress Dugu and Gao over Gao's refusal to endorse Yang Guang, her favorite son, as crown prince, and in 599, at Empress Dugu's urging, Emperor Wen removed Gao from his post.)
In 599, when Sui forces attacked Tujue's Dulan Khan, Ashina Yongyulü, Yang Liang was nominally the overall commander of the operations, but did not go to the front. In summer 600, when Dulan Khan's successor Bujia Khan Ashina Dianjue (), who was a rival claimant to the Tujue throne to the Sui-supported Qimin Khan Ashina Rangan, attacked Sui, Yang Liang was one of the four commanders (along with his brother Yang Guang and the generals Yang Su the Duke of Yue and Shi Wansui () the Duke of Taiping) sent by Emperor Wen to engage Bujia Khan, and they defeated him, although Yang Liang's contribution to the campaign was unclear.
Meanwhile, Emperor Wen much favored Yang Liang, but Yang Liang was becoming ambitious and troubled by the removal of his oldest brother, Yang Yong, as crown prince in 600. (Yang Guang replaced Yang Yong as crown prince.) He therefore persuaded Emperor Wen that his headquarters at Taiyuan was the key to the defense against Tujue, so Emperor Wen permitted him to produce weapons and build up Taiyuan's defenses. Two of his trusted generals, Wang Kui () and Xiao Mohe, both of whom believed that they should have been given greater responsibility by Emperor Wen, also encouraged him to eventually consider rebelling. Yang Liang was further troubled after another brother, Yang Xiu the Prince of Shu, was deposed over charges of wastefulness in 602. (Part of the charges against Yang Xiu, which appeared to have been manufactured by Yang Guang, was that Yang Xiu secretly cursed Emperor Wen and Yang Liang, but there was no evidence indicating that Yang Xiu actually did so or that Yang Liang believed Yang Xiu did or resented Yang Xiu over it.)