The Russo-Japanese War began on 8 February 1904 while Sakharov was in command of the 1st Siberian Army Corps, but it did not see combat before he relinquished command in April 1904. On 5 April 1904, he became had of the field headquarters of the 1st Manchurian Army, participating in the Battle of Shaho in October 1904. On 18 October 1904, he became chief of staff to the commander-in-chief of all land and naval forces operating against Japan, General Aleksey Kuropatkin. He performed those duties until 17 March 1905, and was awarded the Golden Weapon for Bravery with Diamonds on 26 November 1904. He served as a member of the Alexander Committee on the Wounded from 17 March 1905 to 3 January 1906, becoming temporary commander of the 17th Army Corps on 24 September 1905 in the immediate aftermath of the war while continuing to serve on the committee.