三十六计 Thirty-Six Stratagems: 李代桃僵 Sacrifice the plum tree to preserve the peach tree
Chapter 2: Enemy Dealing Stratagems 敌战计
Sun Bin helped Tian Ji (田忌 ) to win a horse race (赛马 ) by putting his best horse in the second race, rather than against other best horses in the first race. The principle also worked in the third and other races. In battle, Sun Bin put his worst troops against Pang Juan's best, his medium troops against the enemy's medium troops and his best troops against the worst of the other side. His best troops quickly wiped out (消灭 xiāomiè) Pang Juan's worst troops and then joined his medium troops to destroy the opposing medium troops. All Sun Bin's forces then combined to overwhelm (攻破 gōngpò) Pang Juan's best troops.
Making this stratagem work can require a careful balancing act (斡旋 wòxuán) and speed (速度 sùdù) can be an important success factor to get an effective sequence of events to quickly gain the upper hand.