Why do people always say that the Qin Dynasty was the first unified dynasty in China, not the Xia Dynasty?

The Qin Dynasty was the first unified dynasty in China, not the Xia Dynasty. It is because the unification of the Xia Dynasty is only the unification of the national title, not the unification of politics, military affairs, culture and ideological cognition. After the Qin dynasty unified the six countries, it established its own writing, unified currency and unified measurement, and the whole world was managed by one regime, which achieved real unity, so the Qin dynasty was the first unified dynasty in China.

when the Xia dynasty was formed, due to the restriction of the productivity level at that time, its ruling scope was limited to the middle and lower reaches of the Yellow River, that is, most parts of Henan, parts of southern Shanxi, Hebei, Shaanxi and Shandong, and only these areas belonged to the direct management of the next field. Moreover, the Xia Dynasty did not have its own fixed country, and it has been moving the capital with the expansion of its territory. Those defeated tribes only surrendered to Xia Wang temporarily, recognizing him as the eldest brother and giving them tribute to cattle, sheep, metal and food, but the Xia Dynasty did not directly rule these areas, and the power of rule was still in the hands of their own tribal leaders. Not only the Xia dynasty, but also the Shang and Zhou dynasties, but their influence expanded. Each of their vassal States had its own writing, currency and standard, and each country only allowed its own currency and writing.

After Qin Shihuang unified the world, he abolished the old fief system, established the county system, unified the writing, unified the currency, and unified unified measurement. The county chiefs all over the country were appointed by the imperial court, and the taxes of every place were collected by the imperial court. Whether economically or militarily, the power was in the hands of Qin Shihuang. To judge whether it is a unified dynasty, it is necessary to form an exclusive central government, the central government has local personnel appointment power, a unified administrative policy, and a unified culture and thought. These four points were completely achieved by the Qin Dynasty.

after Qin Shihuang unified the six countries, under his rule, the system and culture of the Qin Dynasty were unified, which made the Chinese nation truly integrated and laid the foundation for the formation of the Han nationality in the future.