Why did Sima Yi kill a general when he saw the words "Cattle, horses and prostitutes" written on the stone tablet?

Because when Sima Yi saw these four words, he thought that Sima Jia would be replaced by a cow in the future. Sima Yi has taken away the Jiangshan in Cao Zhi's hand, so he is afraid of being taken away by others. Sima Yi happened to see a stone tablet engraved with these four words after Niu Jima. At that time, he didn't understand the meaning of these four words, but later Sima Yi asked the astrologer to divine for his descendants and suddenly remembered these four words.

Sima Yi was just a small Sima under Cao Pi. Later, he usurped Cao Zhi's land step by step, so deep down in his heart, he also knew that all this was ill-gotten gains and was therefore very afraid of losing it. Sima Yi was careful all his life and never allowed this to happen. Therefore, after careful consideration, he made a decision.

At that time, there was a general named Jinniu under Sima Yi, who fought bravely. At first, he was a subordinate of Coss. Later, after the death of Coss, the military power was taken over by Sima Yi, so Jinniu became Sima Yi's subordinate. Taurus participated in many wars, made many contributions, and was very generous and brave.

So Sima Yi prepared a banquet to invite Niu Jinlai to dinner. Jin Niu, without doubt, went with pleasure. But Taurus doesn't know that the wine is poisonous. After dinner, Taurus died, and Sima Yi felt that the stone in his heart had fallen to the ground. Although it seems to us that what Sima Yi did was cruel, just a few words killed a life. However, in the view of people with great ambitions like Sima Yi, anything that may threaten their country cannot be let go, and it is better to kill by mistake.