Lake Baikal, located in the south of Siberia, is the deepest lake in the world and the largest freshwater lake in Eurasia, and is known as the "Pearl of Siberia". Ancient Chinese called it Beihai, and it was once the main area of activity of the tribes of northern China.
Although the Qing Dynasty controlled it for a short time, Lake Baikal was ceded to Tsarist Russia after the Treaty of Nebuchu was signed. Therefore, Lake Baikal was not carved out by the Qing Dynasty, but belonged to "China".
The concept of China in ancient times was different from that of China today, which referred to the country of the Central Plains, the core of the economy, politics and culture. During the Han Dynasty, Su Wu used to herd sheep in the area of Lake Baikal, and at that time Lake Baikal was located in the north of the Xiongnu, so Baikal can be regarded as the territory of the Xiongnu.
Later, the Xiongnu and the Central Plains region married, expressed friendship to the Central Plains, and attached to the Central Plains, so the Xiongnu became a vassal state of the Central Plains.
During the chaotic period of the Northern and Southern Dynasties, there were constant strife among ethnic minorities within "China" until the Tang Dynasty established the "Imperial Protectorate" and included Lake Baikal under its jurisdiction.
This area was then occupied by ethnic minorities during the Five Dynasties and Song dynasties and in the hands of the vassal states of "China". When the Yuan dynasty of the Mongols was established, Lake Baikal became part of its territory.
In the last years of the Ming Dynasty, the Manchus rose to prominence and unified the northeastern region, including Lake Baikal, making it a Qing dynasty jurisdiction. However, the continuous expansion of the Russian Empire made Lake Baikal a disputed area.
The Treaty of Nebuchu was signed in 1689, which defined a large area of land east of the Ergun River to the Trans-Khing'an Mountains as the Sino-Russian border, and confirmed the Heilongjiang River basin as Chinese territory.
The signing of this treaty was an agreement signed by the Qing Dynasty with Tsarist Russia in order to prevent further expansion of Tsarist Russia against the background of its intention to occupy the Heilongjiang region and the occupation of Lake Baikal.
The historical fact that Lake Baikal once belonged to China cannot be ignored, and it was not only during the Qing Dynasty that it was taken out of Chinese territory.