Ma Su (190–228), courtesy name Youchang, was a Chinese military general and politician of the state of Shu Han in the Three Kingdoms period of China. Ma Su had conspicuous talent in military theories and was admired by the Shu chancellor Zhuge Liang. However, a tactical blunder by Ma Su at the Battle of Jieting resulted in Shu being dealt a huge defeat by Zhang He, a general of the rival state of Wei. He was a younger brother of Ma Liang.
Much dramatisation shrouds the death of Ma Su. According to the biography of Ma Su's close friend Xiang Lang, Ma Su was said to have attempted to flee with no further information if it was after or during his defeat at Jieting, but was captured. Following this, he was executed on Zhuge Liang's order and seemed to have face death with dignity. Most of the cultural's depictions concentrate on the latter part such as the historical novel Romance of the Three Kingdoms as well as the Peking opera Loss of Jieting.
Early life
Ma Su was born in Yicheng, Xiangyang Commandery, which is present-day Yicheng, Hubei. He was one of the five brothers in the Ma family, all of whom were renowned for their intellects and commonly known as the "Five Changs" (五常) as their style names all contained "Chang" (常). Although, Ma Su's elder brother Ma Liang was deemed to be the most talented among them all. Aside from his personal talent and military knowledge, Ma Su was described as a man about eight chi tall (approximately 1.84 metres), sociable and good at making friends. With a bright mind and deep expertise.
Together with Ma Liang, Ma Su began his service as an Assistant Officer (從事) under Liu Bei around 209, when Liu Bei succeeded Liu Qi as Governor of Jing Province (covering present-day Hubei and Hunan). In 211, he accompanied Liu Bei into Yi Province. Later, when conflict broke out between Liu Bei and Liu Zhang , Ma Su followed him with the army and served as a military advisor alongside Pang Tong and Fa Zheng. He was appointed as Prefect (令) of Mianzhu (綿竹) and Chengdu (成都). Thereafter, Ma Su was transferred to serve as Administrator of Yuexi (越嶲太守), a troubled commandery in the south. Yuexi was home to numerous indigenous tribes, many of whom refused to accept Liu Bei’s authority. It was the site of a significant tribal revolt led by Gao Ding (高定), the chief of the Sou tribe (叟族) in 218 that was successfully quelled with help from Li Yan.
As Ma Su had talent and ability that surpassed others and enjoyed discussing planning and strategy. Liu Bei's chief advisor, Zhuge Liang had been impressed by him and praised him as an exceptional individual. However, before Liu Bei died in 223, he warned Zhuge Liang that Ma Su's knowledge and speech exceed his real abilities and should not be given important appointments. Still, Zhuge Liang did not heed the warning, and Ma Su was made a personal military Advisor (參軍) soon after Liu Bei's death. The two were very close and would often hold discussions from dawn to dusk.
Southern Campaign
During the campaign against Meng Huo, Ma Su went several tens of li to see Zhuge Liang off. Zhuge Liang told Ma Su: "It's been years since we strategized together, now I ask for your help with your wise and skilled planning."
Ma Su answered to Zhuge Liang as such: "Nanzhong relies on the distance from the capital and its difficult access, and it never submits for long. If we defeat them and leave, tomorrow they would rebel again. Now that you lord are about to engage the whole state and army for a Northern Expedition against the powerful rebels. When the south learn that the authority of the government is weak then they will immediately rebel again. However, if all the tribes with their kinds are exterminated to end future worries then that would be innhumane as this is not the way of the benevolent man. Moreover, it would be a long affair. I learned that, in the way of using troops "attacking the heart is the wisest, attacking city is worst. Psychological warfare is best, armed warfare is the worst." Therefore, I hope that you my lord will focus on subduing their hearts.”
Zhuge Liang followed Ma Su's advice, many times he forgave Meng Huo in order to gain the trust of the people of the South. Hence, until the end of Zhuge Liang’s life, the South did not rebel again.
Performance in Jieting
In 228, Zhuge Liang launched his Northern Expeditions against Wei, at the time there were veteran leaders such as Wei Yan and Wu Yi. Among the army, many advisors suggested appointing either one of them as the vanguard commander however Zhuge Liang disagreed with the majority and chose Ma Su to command the army at the front instead.