The Third Reserve Army of Observation was a Russian army created during 1811 as an impromptu force to watch the Austrian frontier when it became apparent that the Austrian Emperor would possibly send troops into Russia as part of the French invasion of Russia. It had 44,000 men and 168 guns. Alexander Tormasov took command of the army on 27 March 1812. It was renamed the Third Western Army on 30 September 1812 following its merger with the Army of the Danube. The Third Western Army, led by Pavel Chichagov, failed to cut off Napoleon's army's retreat, though it followed the French into Poland the following January.
Third Reserve Army of Observation Wikipedia
Commander-in-Chief General of the Cavalry Alexander TormasovGroup of General of the Infantry S. M. Kamensky 1st
Group of General Lieutenant E. I. Markov
Group of General Lieutenant Baron F. V. Osten-Saken
Cavalry group of the General Major Graf K. O. Lambert
Chief of Staff General Major I. N. Inzov
General-quartermaster - Colonel R. E. Renni
Duty General - Fligel-Adjutant Colonel K. F. Oldekop
Chief of Artillery - General Major I. Kh. Sivers
The total strength of the Army was 60 battalions, 76 squadrons, 10 cossack regiments, and 168 guns.