Why did Mongolia have autonomy under Chinese suzerainty instead of full independence after 1911?

Following the collapse of Qing rule in 1911, Mongolia declared independence; however, it failed to achieve full international recognition as a sovereign state due to the geopolitical interests of Russia and China.

While the Bogd Khan’s government considered Mongolia independent, Russia characterized the region as "autonomous" to balance its own diplomatic objectives. This position was formalized in a 1913 declaration between Russia and China, which asserted that Mongolia remained under Chinese suzerainty. This status was subsequently reinforced by a 1915 tripartite treaty among Russia, China, and Mongolia, which legally obligated the Bogd Khan’s government to accept autonomy under Chinese suzerainty.12

As a result of these diplomatic constraints, Mongolia was unable to secure full independence at that time, nor could it unite Inner and Outer Mongolia or prevent Russia from colonizing Tuva. It was not until the 1945 Yalta Conference agreements and a subsequent plebiscite that Mongolia moved toward formal recognition of its independence, which was eventually acknowledged by the Republic of China in 1946.1234