Manchukuo

During the 20th century, Manchukuo was a puppet state.

Source: tatoeba (814498)

Manchukuo was a Japanese puppet state.

Source: tatoeba (13609843)

Originally speaking, the Heilungkiang Valley, amongst other Russian possessions in the Far East, had been within Manchurian domain until the middle of the nineteenth century, when it was absorbed by Russia. For us, therefore, it is difficult to regard all Manchuria now within the territory of new Manchukuo and Russian Manchuria of today separately. Now that the Manchukuo State has become absolutely independent and placed under Japanese protection, so to speak, the destiny of Russian possessions in the Far East may be easily imagined.

Source: wiktionary

When evacuation was effected it would be “to the Great Wall”, not to the Jehol boundary. Since the Great Wall dips well into northern Hopei, an area of several thousand square miles was thus added to the territory of Manchoukuo.[...]In actual operation, the cordon sanitaire of the “demilitarized” zone was far from reciprocal. Under the terms of the Tangku Truce, Chinese armed opposition to Manchoukuo was clearly prevented.

Source: wiktionary