At the time, tensions were rising at the Sun–Liu border in Jing Province as both sides became more suspicious and wary of each other. Around July 215, Sun Quan asked Liu Bei to "return" three commanderies in southern Jing Province –
Changsha, Lingling (零陵; around present-day
Yongzhou, Hunan) and Guiyang (桂陽; around present-day
Chenzhou, Hunan) – since the latter already had a new base in
Yi Province. However, Liu Bei refused because he believed that the three commanderies were crucial in his efforts to unify China. Sun Quan decided to seize the three commanderies by force. He stationed himself at Lukou (陸口; at Lushui Lake near present-day
Chibi, Hubei) while ordering
Lü Meng,
Ling Tong and
Lü Dai to lead troops to attack the three commanderies, and Lu Su to lead 10,000 troops to
Yiyang to block Guan Yu.
Lü Meng capturing the three commanderies Lü Meng wrote to the administrators of the three commanderies to ask them to submit to Sun Quan. All of them agreed except Lingling's administrator, Hao Pu (郝普). In the meantime, upon learning of Sun Quan's advances, Liu Bei returned from Yi Province to
Gong'an County and ordered Guan Yu to lead troops to stop Lü Meng and take back the three commanderies. After hearing that Guan Yu and his army was heading their way, Sun Quan sent an urgent order to Lü Meng, ordering him to give up on Lingling and lead his troops to
Yiyang to assist Lu Su. When Lü Meng pacified
Changsha, he passed by Ling County (酃縣; east of present-day
Hengyang, Hunan) and met Deng Xuanzhi (鄧玄之), an old friend of Hao Pu. He planned to use Deng Xuanzhi to trick Hao Pu into surrendering. That night, Lü Meng summoned all his officers and gave them instructions on how to attack Lingling the following morning, without telling them that Sun Quan had given orders for them to give up on Lingling and move to Yiyang. He lied to Deng Xuanzhi that Liu Bei was besieged in
Hanzhong by Cao Cao's general
Xiahou Yuan and that Guan Yu was occupied in a battle at Nan Commandery. He then asked Deng Xuanzhi to help him persuade Hao Pu to give up on Lingling. Deng Xuanzhi went to see Hao Pu later and conveyed Lü Meng's message. Hao Pu became afraid when he heard that he had been isolated, so he agreed to surrender and asked Deng Xuanzhi to lead him to Lü Meng. When Lü Meng met Hao Pu, he revealed the truth, clapped his hands and laughed. Hao Pu became wrecked with guilt when he learnt that both Liu Bei and Guan Yu were actually free to reinforce Lingling but it was too late. Lü Meng left Sun He (孫河) behind to guard the three commanderies while he headed towards Yiyang per Sun Quan's order.
Standoff at Yiyang between Guan Yu and Gan Ning In the meantime, Guan Yu claimed to be leading an army of 30,000. He selected 5,000 of his best troops, led them to the upstream shallows located some 10
li away from
Yiyang, and planned to cross the shallows at night. Lu Su held a discussion with his subordinates on how to deal with Guan Yu. At the time,
Gan Ning, who had only 300 men under him, told Lu Su: "If you give me another 500 troops, I will go to confront Guan Yu. I assure you that Guan Yu will not dare to cross the waters when he hears of my approach. But if he does, I will capture him." Lu Su then chose 1,000 troops and put them under Gan Ning's command. Gan Ning headed towards Guan Yu's position at night. As Gan Ning expected, Guan Yu did not cross the shallows and instead ordered his men to make camp there. That place was thus named 'Guan Yu's Shallows' (關羽瀨).
Negotiations between Lu Su and Guan Yu Lu Su invited Guan Yu to attend a meeting to discuss the dispute. During the negotiations, both sides stationed their soldiers more than 100 paces away from the meeting area, while the officers present at the talks were each armed with nothing more than a sword or blade weapon. This event is hence sometimes referred to as "attending a meeting armed with only a sword" (單刀赴會). Lu Su told Guan Yu: Before Lu Su could finish what he was saying, an unnamed person interrupted him: "Whoever has the ability to govern the land shall have control over it. Isn't it so?" Lu Su angrily rebuked that person in a firm and stern tone. Guan Yu drew his sword, stood up and said: "This is a state-level problem. We can't hope to understand it." He left after that.
Wei Zhao's
Book of Wu (吳書) provided more details on the meeting. Before the talks started, Lu Su's subordinates feared that Guan Yu would try to harm Lu Su, so they advised Lu Su against attending the meeting. However, Lu Su replied: "It's better for us to settle this dispute in a peaceful manner. Liu Bei may have acted against our lord's interests, but we haven't agreed on who is right and who is wrong. Do you think Guan Yu will dare to do something as rash as killing me at this point in time?" Lu Su then met Guan Yu, who told him: Lu Su replied: Guan Yu did not respond to what Lu Su said.
Peaceful settlement Although the talks between Lu Su and Guan Yu were inconclusive, the Sun–Liu territorial dispute ultimately ended by the end of August 215 when Liu Bei decided to give in upon learning that his base in Yi Province was potentially under threat. This was because Cao Cao was attacking
Hanzhong Commandery, then under the control of the warlord
Zhang Lu. As Hanzhong was the "northern gateway" of Yi Province, if Cao Cao succeeded in seizing Hanzhong from Zhang Lu, he would be able to launch attacks on Yi Province from Hanzhong. Liu Bei thus decided that it was better for him to make peace with Sun Quan at the moment, and shift his focus towards countering Cao Cao. Liu Bei and Sun Quan then withdrew their forces after agreeing to divide the territories in southern Jing Province between their respective domains along the
Xiang River: Liu Bei would keep Nan, Lingling and Wuling commanderies in the west, while Sun Quan would take Changsha, Jiangxia and Guiyang commanderies in the east. ==Aftermath==