All of the following are names of the Seven Warring States EXCEPT:

The story behind the answer

Zhai (翟) is not one of the Seven Warring States; the seven were Qi (齊), Chu (楚), Yan (燕), Han (韓), Zhao (趙), Wei (魏), and Qin (秦). These were the dominant powers in the Warring States period (5th–3rd centuries BCE); smaller polities and tribal groups—sometimes labeled with characters like 翟—existed but were not counted among the “Seven.”

This tumultuous era saw sweeping military and administrative reforms and the flowering of philosophy. Qin, strengthened by Legalist reforms (notably Shang Yang), conquered the others and unified China in 221 BCE. Memory tip: “QQ Can You Help Zhao Win?”—QQ (Qin, Qi), C (Chu), Y (Yan), H (Han), Z (Zhao), W (Wei).