29 July-6 August 1812 -- Napoleon rests the troops
The harassment by Russian troops on the French flanks and logistics problems prevented the French from taking on the Russians and destroying them piecemeal. By this point in the campaign discipline was already failing in some corps, looting was becoming more widespread, and the French received little comfort in foraging attempts. Napoleon halted the French advance and rested the army for seven to eight days between Velizh and Mogilev.

16-18 August 1812 -- Smolensk
The Russians, with a newly united army of from 120,000 to 130,000 under Barclay de Tolly, under pressure from the Czar to halt the French advance, prepared to take a more energetic attack on the French, but slow work hampered their movements. Fortunately for the Russians, the failure prevented Napoleon from competing a turning movement. Had the trap succeeded, it might have crushed the Russian defense. The Russians hurriedly retreated to Smolensk.

The French Grand Armée consisted of from 175,000 to 250,000 men at this point. In the battle, 50,000 French troops, in an engagement with 60,000 Russians, attacked the city and were able to capture only two suburbs. Fearing the French might move north and cut off their retreat and communications, the Russians evacuated under the cover of darkness and set fire to the city.

The Russians continued their eastward retreat, frustrating the French by moving back in good order. By this point in the invasion, nearly all segments of the Russian population were united against the foreign aggressors. The partisan movement began an active struggle against the French, denying them aid, food, and shelter, and killing stragglers. Cossack irregulars and organized partisan groups harassed isolated small corps, supply trains, and foraging parties.

Casualties:
French: over 10,000; Russian: over 9,000

Troop strength:
French: 230,000; Russian: