What exactly are the sixteen states of Youyun, which made the Northern Song Dynasty always want to recover this place?

Sixteen states in Youyun, also known as sixteen states, are roughly equivalent to Hebei, Shanxi, Tianjin and Beijing now, so they are natural barriers to resist ethnic minorities in the Northern Song Dynasty. Sixteen states of Youyun are related to whether the Northern Song Dynasty can sit back and relax and whether the people can live and work in peace and contentment. The most important thing is that the grassland in the north is vast, and most farmland in the south is not suitable for raising horses. Therefore, the Northern Song Dynasty always wanted to take back the sixteen states of Youyun into its own hands to raise horses and improve the military strength of cavalry.

Song Taizu, Song Taizong and Song Huizong want to take back these 16 states in different ways. Song Taizu just succeeded to the throne, and his strength is not very strong. So the first consideration is not to solve the problem with war, but to solve it with money. He wanted to redeem the sixteen states of Youyun with a large sum of money, but the Liao people were not stupid and simply refused. Song Taizu is going to worry about warriors, attack Liao and recover sixteen states of Youyun by force, but the final plan is still.

Song Taizong tried to use the afterglow of the destroyed Northern Han Dynasty to make a vigorous effort, but he failed twice. Finally, Song Taizong had to retreat. The reason for the failure is still in Song Taizong. He assembled an army of 200,000, divided into three groups. But he was worried that these generals would support him, so Song Taizong directly ruled 200,000 troops. Finally, because of tactical mistakes, Song Taizong didn't beat the Liao people three times.

Song Huizong used the golden talent to recover the deep and remote cloud, but there are still fifteen states that have not recovered it. From then on, it was not until the Ming Dynasty that sixteen states of Youyun were recovered.