The eastern limit of the entire territory was never definitively settled during the Second World War. In the event that the Axis forces would have occupied the remainder of the unconquered Soviet Union, a delimitation of the region along the 70° east longitude line was proposed by the Empire of Japan in late 1941, which would have marked the western limit of its own holdings in the Greater East Asia Co-Prosperity Sphere.[7] An amended version of this suggestion moved the frontier further eastwards, to the eastern border of the Central Asian republics with China, and along the Yenisei river in Siberia.[8]