Guan Yu claimed he had 30,000 troops. He selected 5,000 elite soldiers, headed 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 had only 300 men under him and he told Lu Su, "If you give me another 500 troops, I will go to confront Guan Yu. I assure you that Guan Yu won't 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 set up camps there. That place was thus named 'Guan Yu's Shallows' (關羽瀨).