According to the "Book of Jin", when Sima Fu wrote to Sima Yi to ask him about the situation at the Wuzhang Plains, Sima Yi replied by saying: "Zhuge Liang has big ambitions but he fails to recognise opportunities. He is full of wits but not decisive. He likes leading troops into battle even though he does not have much authority over them. Even though he has 100,000 troops under his command, he has already fallen into my trap and I'll certainly defeat him." When Zhuge Liang's envoy visited Sima Yi's camp, the latter allegedly inquired about his sleeping and eating habits, along with how busy he was. When told how Zhuge Liang consumed little and didn't sleep much, Sima Yi said to his men: "Zhuge Kongming takes little food and does much work; how can he last long?"