The action at Inkovo (8 August 1812) was a minor Russian victory during a short-lived Russian offensive that came soon after the main Russian armies had united at Smolensk.
At the start of Napoleon's invasion of Russia the two main Russian armies, Barclay de Tolly's 1st Western Army and Bagration's 2nd Western Army, were dangerously separated. Napoleon spent the first six weeks of the campaign attempting to defeat one or the other of these armies before they unite, but each of his efforts failed, and on 4 August the two Russian armies met up as Smolensk on the Dnieper.
At this point the French were located between Vitebsk on the Dvina in the north and Orsha on the Dnieper in the south. Both sides decided to go onto the offensive. Napoleon's plan was for his army to move south to cross the Dnieper east of Orsha and then advance east along the south bank to catch the Russians at Smolensk (ideally while they were looking for him north of the river).
On the Russian side Barclay de Tolly came under intense pressure to go onto the offensive. After a council of war on 6 August he agreed to attack west on the north bank of the Dnieper. The Russian offensive began on 7 August, but on the following morning Barclay de Tolly received a false report of a French advance towards Porechye, north of Smolensk. Barclay de Tolly abandoned the move west and instead moved slowly north-west to guard against this imaginary attack.
The altered orders didn't reach General Platov, the commander of the Cossack corps, and he continued his advance west. This meant that his troops clashed with General Sebastiani's 2nd Light Cavalry Division, part of Montbrun's II Cavalry Corps near Inkovo.
The battle slowly escalated in scale during the day. It began with a clash between French outposts near Loshnya and the Russian advance guard under Major General Vasily Denisov.
The French outposts were joined by General Montbrun's troops and they pushed back the Russians. As the French approached Molevo Boloto they ran into the rest of Platov's corps and were forced to retreat. The French 8th Light Cavalry Brigade, which had been most heavily involved, had to retreat for two miles before it was reinforced by the 7th Light Cavalry Brigade. The combined French force then repulsed the pursuing Russians.
Platov decided to launch a full scale assault on the French position. Kuteynikov's brigade was to attack on the right, IIovaysky's brigade on the left and Platov in the centre. The Russians pushed the French back some way, although they were slowed up by French reinforcements, first the 16th Light Cavalry Brigade and then the 14th Light cavalry Brigade (part of the corps cavalry with Ney's III Corps). By the time the fighting ended the Russians were only three miles east of Rudnya, well to the west of Inkovo.
The action of Inkovo was a clear Russian victory. The French lost 600 men, including 11 officers and 300 other ranks captured. However it had a surprising negative impact on the Russian army. In the short term Barclay de Tolly was worried that the fighting would alert the French to his offensive, and thus trigger a major French counterattack that might have led to a serious Russian defeat. As a result the Russian offensive faded away, allowing Napoleon to continue his Smolensk manoeuvre.
Perhaps more serious was the impact on the relationship between Russian and 'foreign' officers in the Russian army. The 'foreign' contingent included just about anyone with any element of foreign blood, never mind how obscure (including Barclay de Tolly) and anyone from the subject nations of the Russian Empire. After the battle the Russians captured Sebastiani's headquarters, where they found a message from Murat giving information on the Russian offensive. The Russians immediately assumed that one of the 'foreign' officers must be a spy, poisoning the atmosphere at headquarters. In the end there turned out to be a far more innocent explanation. Prince Lubomirski, a Polish officer in the Russian army, had sent a warning message to his mother, who lived in the area about to be attacked. By chance Murat was billeted in the Prince's house and had captured the message.