China is a good place, and the places where we can grow grain have all been drawn to us, and the rest are wild lands. But these are bad places for us, and there are still people who can survive and grow.
Needless to say, the northern desert has never stopped the replacement of nomadic peoples. There are also human activities on the Qinghai-Tibet Plateau in the southwest direction, and by the time of the Tang Dynasty, the Tibetan regime was developed and has always been against the Tang Dynasty. There are countless ethnic groups in the western region and further west, and even the history is longer than that of the Central Plains.
Therefore, it is not enough to occupy a place suitable for farming, because the surrounding Hu people may kill at any time to harass and rob, and may also want to be the masters of the Central Plains and treat the farmers as their own cows.
The Northern Song Dynasty is a clear negative example, although extremely rich, the national defense posture is very bad. In order to defend the Liao state, the Hebei Plain had to be built into a large fortress. The Northern Song Dynasty did not hesitate to drain the lake water in Northern China, but also to reclaim paddy fields everywhere, the Northern Song Dynasty did not want to harvest more rice, but wanted to prevent the Liao State from riding iron.
Shaanxi was the front line of the war for hundreds of years, and the Guanzhong Plain was once the granary of the unification of the six kingdoms of the Qin State, but in the Northern Song Dynasty, it could not even provide for itself, and it needed to continuously transport grain and grass to maintain the supply of the northwest border defense army. As soon as the Hexi Corridor was lost, the hinterland of the Central Plains was exposed to the enemy's blade and had to garrison heavy troops in Shaanxi.
From the perspective of national defense, modern China has reached a very perfect defensive posture on land, the agricultural areas are all far away from the border, with enough defense depth, not like the Mongol super invader, generally will not threaten the survival of the Central Plains Dynasty.
The East is the sea, in ancient times there was no invader, our ancestors never considered the matter of coastal defense, shipbuilding and going to the sea is just to do business, by the way, shake the mighty wind, let the overseas clan know that the Central Plains have a new master.
The northeast was not much of a threat for a long time, it was relatively cold, the mountains and dense forests made the Hu people smaller, and they could hold the territory by relying on the grain of Liaodong. Therefore, the Hu people in the northeast have not broken through the Liaodong defensive line.
However, the Daxing'an Mountains are a relatively gentle mountain range, and the Northeast Hu people crossing the Daxing'an Mountains into the Mongolian steppe will immediately swell sharply and become a major problem for their confidants, such as Xianbei, Khitan and Jurchen. Moreover, the road from the northeast to Guannei is not only the Western Liaoning Corridor, but also the Mongolian steppe to Gyeonggi.
Because the Manchu Qing controlled the Mongolian steppe, they believed that the northeast could rest in peace and relaxation, without the need for heavy troops to defend. I did not expect that the next enemy would come from Siberia further north, resulting in the loss of the outer northeast and the sharp deterioration of the defense environment in the northeast.
The loss of Outer Mongolia by the Republic of China not only opened the gateway to the north, but also put the northeast in danger of being caught between three sides. Fortunately, Inner Mongolia is still in our hands, and unlike the Ming Dynasty, the main energy is pinned down on the defense system with the capital Beijing as the core. Therefore, Outer Mongolia and Outer Northeast Are still in our hands, which not only greatly increases the land area, but also makes the North truly stable.
The Hexi Corridor in the northwest direction is a gift from heaven to the Central Plains Dynasty, and the narrowest point is only a few kilometers, starting from the time emperor Wudi built the four cities of Dunhuang, Jiuquan, Zhangye, and Liangzhou, and foreign enemies could hardly break through the Hexi Corridor. Due to the abundant meltwater of the snow-capped mountains, the Hexi Corridor was enough to garrison the troops and even divide themselves.
The Western Regions were one of the keys to China's emergence as a world power, and without Emperor Wudi of the Han Dynasty chiseling through the Western Regions and opening up the Silk Road, Europeans did not know when they would discover China's existence. Only when the Qing Dynasty changed the western region to Xinjiang was China eligible to compete for the world's islands. Qianlong quelled the Dzungar rebellion, and Zuo Zongtang quelled the Agubai rebellion, both of which made great contributions to China.
Bordered by Sichuan and Yunnan in the east and the western region in the north, the Qinghai-Tibet Plateau posed a great threat to the Central Plains, and coupled with the extreme plateau climate, it was almost an insurmountable obstacle for the Central Plains Dynasty. The Tang Dynasty failed to conquer Tubo on the Qinghai-Tibet Plateau in its heyday, which shows the hardships of this plateau.
The Mongols made a contribution here, incorporating the Tibetan Plateau into their territory, and although the Ming and Qing dynasties did not have a long-term garrison, sovereignty still belonged to China without question. It was not until New China truly realized the garrison on the plateau and completely determined the ownership of sovereignty. With the Qinghai-Tibet Plateau, China is qualified to participate in the affairs of the South Asian subcontinent and make greater contributions to world peace.
Yunnan was China's main link to Southeast Asia and was incorporated into China's territory as early as the Warring States period. Although the qing dynasty lost part of its territory, its impact was not great.
All in all, in addition to the traditional Eighteen Provinces of Han China, Qinghai-Tibet, Xinjiang, and Inner Mongolia are natural barriers that can be attacked and defended. If China does not have actual control over these places, then China's international status will inevitably decline by several levels, and defense pressure will be greatly improved.
Unfortunately, the Outer Northeast and Outer Mongolia were lost at the end of the Qing Dynasty and the Republic of China, weakening the potential for development to the north. Otherwise, China's territory will reach more than 13 million square kilometers, plus bits and pieces of lost land, 15 million is also expected.