When did the Operation that seized the territories formally claimed by  Manchukuo began
Manchukuo Manchukuo (: "Mǎnzhōuguó"literally: " State of Manchuria" ) was a puppet state in Northeast China and Inner Mongolia, which was governed under a form of constitutional monarchy. The area, collectively known as Manchuria by westerners and Japanese, was designated by China's erstwhile Qing Dynasty as the "homeland" of the ruling family's ethnic group, the Manchus. In 1931, the region was seized by Japan following the Mukden Incident and a pro-Japanese government was installed one year later with Puyi, the last Qing emperor, as the nominal regent and emperor. Manchukuo's government was abolished in 1945 after the defeat of Imperial Japan at the end of World War II. The territories formally claimed by the puppet state were first seized in the Soviet invasion of Manchuria in August 1945, and then formally transferred to Chinese administration in the following year.
266th Rifle Division (Soviet Union) It was first formed in July 1941 from an NKVD division and destroyed during the later stages of the Battle of Smolensk in August. It was reformed in December and destroyed in the Second Battle of Kharkov in May 1942. The 266th was formed for a third time in August 1942, and fought in Operation Little Saturn, the Donbass Strategic Offensive, the Jassy–Kishinev Offensive, the Vistula–Oder Offensive, and the Battle of Berlin. Postwar, the division briefly remained in Germany before being withdrawn to Stalingrad, where it became a separate rifle brigade. In 1953 it was expanded into the 68th Mechanized Division, and in 1957 it became the 117th Motor Rifle Division. In 1965 it was renumbered the 266th Motor Rifle Division, and a year later transferred to the Soviet Far East. The division was based in Amur Oblast until it was reduced to a storage base in 1989.