Later Zhou Shizong never advocated the settlement of the Khitan first, on the contrary, the strategic idea of unifying the whole country of "first south and then north, first easy and then difficult" was first put forward by Wang Pu, the heavy minister of Later Zhou, but Later Zhou Shizong's implementation was not thorough, and his focus was still on the Khitan in the north and the Sixteen Prefectures of Youyun that had been ceded away.
As the most outstanding emperor of the Five Dynasties and Ten Kingdoms period, Later Zhou Shizong Chai Rong worked hard to unify the cause and set up the ambition of "opening up the world in ten years, feeding the people in ten years, and bringing peace in ten years". In the early period of the reign of Later Zhou Shizong, there was no clear strategic way of first going south and then north or first north and then south, and while using troops against the Khitans, in order to maintain the stability of the rear, he also actively used troops against the south. During his reign, the Western Defeat of Later Shu and the reconquest of Qin, Jie, Feng, and Chengsi Prefectures; the southern destruction of southern Tang, the fourteen prefectures of Huainan in the north of the jiangsu province, forcing the southern Tang emperor Li Yu to claim the title of emperor; the northern breaking of the Khitan and the three states of Lianke Sanguan, if it were not for the early death of the young, youyun Sixteen Prefectures would most likely be recovered at the hands of Later Zhou Shizong.
Chai Rong's main target was still the Khitans, and the Successive Northern Expeditions to the Khitans were aimed at the Sixteen Prefectures of Youyun.
Since the Sixteen Prefectures of Youyun were ceded to the Khitan by The Later Jin Dynasty Emperor Shi Jingyao, the Later Han Dynasty Zhou dynasty has been working to reclaim it. The fall of the Later Jin and Later Han states was all because after youyun sixteen prefectures were ceded to the Khitans, the Central Plains barrier was no longer there, and the Khitan army smoothly moved south from Youzhou and Yunzhou, not only destroying the Later Jin, but also posing a great threat to the rule of the Later Han.
Before solving the Khitan problem, Chai Rong had used troops against the southern states many times. In the second year of Xiande (955), he marched west to Later Shu and recovered the four states of Qin, Jie, Feng, and Cheng. In November of the same year, Chai Rong personally conquered the Southern Tang for the first time, and shared troops with the Southern Tang three times, and all of them were pro-conquests, and finally took the Fourteen Prefectures of Southern Tang and Northern Huainan, forcing Southern Tang to submit to it. Chai Rong's several successful southern expeditions greatly shocked the various separatist forces in the south and eliminated the worries of the subsequent Northern Expedition.
For the use of troops in the south, Chai Rong's purpose is not to destroy its country, if the Later Zhou raises the strength of the country to march south, then the Khitan will come to attack, the Khitan is much stronger than the southern countries, regardless of military strength or non-commissioned combat effectiveness, the big trouble of the Later Zhou is the Khitan, not the south of these countries whose strength is obviously inferior to the Later Zhou, attacking the Southern Tang of Later Shu can play a role in knocking the mountains and shaking the tiger. Therefore, from the sixth year of Later Zhou Xiande (959), Chai Rong focused most of his energy on the Northern Expedition to the Khitans.
During the reign of Zhao Kuangyin, the grandfather of the Song Dynasty, he was committed to national unification based on the chancellor Zhao Pu's "first south and then north, first easy and then difficult", and unlike Later Zhou Shizong Chai Rong, Zhao Kuangyin's southern expedition was to completely destroy these separatist forces, and then turn to the Khitan in the hope of recovering the Youyun Sixteen Prefectures that were ceded to the Khitan by the Later Jin Dynasty Emperor Shi Jingyao.
It is worth mentioning that the strategic idea of "easy first and then difficult" was actually first put forward by Wang Pu, a heavy minister of Later Zhou, in his "Pingbian Strategy", and Later Zhou Shizong himself recognized this strategic approach, Zhao Kuangyin followed Zhou Shizong to participate in the war against Southern Tang in the Later Zhou Dynasty, and after three years of hard fighting, he won the Fourteen Prefectures of Huainan in Southern Tang. It was obviously more difficult to fight the Southern Tang first, and Zhao Kuangyin had a clear understanding of this as a participant in the attack on the Southern Tang Dynasty, so he also made major adjustments to the objectives and order of the attack, that is, "taking Bashu first" and "second to Guangnan and Jiangnan", so that the process of unifying the south progressed smoothly.
At the same time, the south has experienced few wars, the people live in peace, and the fertile wilderness is thousands of miles, the degree of prosperity is higher than that of the north, and the wartime grain and salaries also depend on the south, which is what we want to say about the idea of "getting rich first and then taking later", which has pacified the southern countries, then the country has all it needs, and with strong financial and material resources as support, it is possible for the Northern Song Dynasty to gather the strength of the whole country to deal with the Khitans.
Zhao Kuangyin's strategy of first going south and then north was in line with the situation at that time when the south was weak and the north was strong. However, at the same time that the Northern Song Dynasty gradually completed the unification of the south, the national strength of the Liao State (Khitan) also began to reach its peak, and many attacks on the Northern Han in the early Song Dynasty had to withdraw their troops because the Liao State sent troops to help. It was not until after the unification of the south that the Northern Song Dynasty made full use of the manpower and material resources of Jiangnan and Bashu to concentrate on the northern expedition, and finally forced the Northern Han to surrender, ending the chaotic period of the division of the Five Dynasties and Ten Kingdoms.
Strictly speaking, the Later Zhou Shizong Chai Rong adopted the strategy of "first easy and then difficult", but not as thorough as the Song Taizu Zhao Kuangyin did, the heart of the Later Zhou and northern Song dynasties are extremely powerful Liao (Khitan), from the author's personal point of view, it is obvious that Zhao Kuangyin's strategic thinking of "first easy and then difficult" is more in line with reality, later Zhou and Northern Song, in a short period of time, can not solve the problem of the Liao state, and even the recovery of Youyun Sixteen Prefectures are facing great obstacles, rather than self-consumption with the Liao state in the long-term conquest, It was better to first pacify the south and then concentrate all its efforts on dealing with the Liao state, which should have been the wisest and forward-looking choice at that time.