The Battle of Omsk was a major battle in and around the Siberian city of Omsk between the Allied Powers and the Asian Powers from December 1925 until February 9, 1926, when the Chinese elected to withdraw their soldiers in their disastrous retreat homewards from February until April 1926. The battle was contested for the major railroad hub and the industrial heart of Siberia - if Omsk fell, Siberia's capital of Novosibirsk was at direct risk and the Allied war effort would have taken a potentially irreparable blow. Fought with an Allied force of Siberian, American, Alaskan and French Russian volunteers against an exclusively Chinese army almost a million men strong, the battle was a lengthy campaign of attrition that after forty-seven days ended as a disaster for the Chinese. It was the crux of the Western Theater of the 1925-26 Winter Offensive, the bloodiest campaign in human history. After the decision of Chinese military leaders not to reinforce the Western Theater arrived to Chinese commander Li Qong in early February, two Chinese divisions surrendered to Siberian forces led by Nikolai Rabyshin while the remainder retreated less than ten percent of whom returned home.
Omsk is generally regarded amonst military historians as the most barbaric and bloody battles in the Pacific War, if not human history.