Warlord's Kites, The (Warlord's Series)

All is calm in the warlordís palace, and the artistís apprentice Chuan sits with his friend Jing Jing, watching the sunset, when an invading army approaches. Jing Jing comes up with an ingenious solution using Chuanís knowledge of calculating area as well as his handmade paper and ink to frighten the troops into leaving.