King Xiang sent You Sun and Bofu to Zheng Guo to intercede for Slip, why did King Xiang attack Zheng

The main reason is that the situation has changed, otherwise he doesn't want to, so for the sake of the country, he has to use Zhai people to crusade against Zheng Guo, otherwise his country will be in danger.

There are no eternal friends between emperors, and there are no eternal interests, some are only eternal interests, so driven by power, King Xiang will use the Zhai people to crusade against Zheng Guo, and then get the greatest benefits.

There is no necessary connection between these two things, the king is mainly in the interests of the country, he can intercede for the interests of the country, or he can attack Zheng in order to have a larger territory.

Because King Xiang thought that the situation was out of control, Zheng Guo did not forgive Slip, so he attacked Zheng Guo.

Because the international situation is changing, the decisions made will change as the situation changes. Probably at first they needed Zheng Guo to help them. But then he may have found a new alliance and didn't need it.

The monarch naturally has to think about himself and the country, so he will have his own plans, and not attacking at the beginning does not mean that he will not attack in the future, but the time is not ripe, and he will definitely annex the land and population when he thinks about the development of the country in the later stage.

Because emperors have the ambition to dominate the world, it is said that he wants to defeat Zheng Guo later because his ambition is to be satisfied, and he wants to sit firmly in his own country.

In 229 BC, Qin sent the general Wang Jian to lead his troops to attack Zhao, and in 228 BC, the Qin army entered Handan, and the king of Zhao surrendered with a map, and the state of Zhao died.

However, it is worth mentioning that at this time, Gongzi Jia was the king of Daidi, that is, he established the Daiguo, and continued to survive. And has been insisting on resisting Qin, and finally when Qin attacked Liaodong, he destroyed the dynasty in one fell swoop, and at this time Zhao was really destroyed.

This is like the Three Kingdoms, Liu Bei and Sun Quan can join forces to attack Cao Cao, or they can lead troops to attack Sun Quan alone, and the relationship between them can be friends or enemies.

The struggle between countries is not something that can be explained clearly in one or two sentences, but that emperor has no ambition to dominate the world? Even if their relationship eased at that time, for the sake of their own country, they would still get rid of all threats around them.