Siege of Smolensk
Commonwealth forces in Smolensk were composed of the Smolensk garrison (about 1,600 men with 170 artillery pieces under the command of the Voivode of Smolensk, Aleksander Korwin Gosiewski), strengthened by the local nobility, which formed a pospolite ruszenie force of about 1,500 strong. The city's fortifications had also recently been improved with Italian-style bastions.
Shein constructed lines of circumvallation around the fortress. Using tunnels and mines, his forces damaged a long section of the city wall and one of its towers. Russian heavy artillery, mostly of Western manufacture, reached Smolensk in December 1632 with even heavier guns arriving the following March. After a preliminary artillery bombardment, Shein ordered an assault, which was repulsed by the Polish defenders. Nonetheless the siege was progressing; Smolensk's fortifications were being eroded, and the defenders were suffering heavy casualties and running out of supplies. By June 1633, some soldiers started to desert, and others talked of surrender.
Despite these difficulties, the city, commanded by Deputy Voivode Samuel Drucki-Sokoliński, held out throughout 1633 while the Commonwealth, under its newly elected King Władysław IV, organised a relief force. The Sejm had been informed about the Russian invasion by 30 October 1632, and, starting in November, had discussed the possibility of relief. However, the process was delayed until the spring of 1633, when the Sejm officially sanctioned a declaration of war and authorised a large payment (6.5 million zlotys, the highest tax contribution during Władysław's entire reign) for the raising of a suitable force. The intended relief force would have an effective strength of about 21,500 men and would include: 24 chorągiews of Winged Hussars (~3,200 horses), 27 chorągiews of light cavalry—also known as Cossack cavalry but not composed of Cossacks—(3,600 horses), 10 squadrons of raitars (~1,700 horses), 7 Lithuanian petyhor regiments (~780 horses), 7 large regiments of dragoons (~2,250 horses), and ~20 regiments of infantry (~12,000 men). Over 10,000 of the infantry would be organized based on the Western model, previously not common in Commonwealth armies.
Meanwhile, Field Hetman of Lithuania and Voivode of Vilnius, Krzysztof Radziwiłł, and Voivode Gosiewski established a camp about 30 kilometres (18.6 mi) from Smolensk, moving from Orsha to Bajów and later, Krasne. By February 1633, they had amassed around 4,500 soldiers, including over 2,000 infantry, and were engaged in raiding the rear areas of the Russian besiegers to disrupt their logistics. Hetman Radziwiłł also managed to break through the Russian lines on several occasions, bringing about 1,000 soldiers and supplies into Smolensk to reinforce the fortress and raising the defenders' morale.
By the summer of 1633, the relief force, led personally by the king and numbering about 25,000 (20,000 in the Polish-Lithuanian army, according to Jasienica), arrived near Smolensk; they reached Orsha on 17 August 1633. By the first days of September, the main body of the relief forces approaching Smolensk numbered around 14,000. The Russian army, recently reinforced, numbered 25,000. Only when Cossack reinforcements, led by Tymosz (Timofiy) Orendarenko and numbering between 10,000 to 20,000, arrived on 17 September would the Commonwealth army gain numerical superiority. The Cossacks under Orendarenko and Marcin Kazanowski would raid the Russian rear lines, freeing the Polish-Lithuanian units under Radziwiłł and Gosiewski to join the effort to break the siege.
Władysław's brother, John II Casimir, commanded one of the regiments in the relief army. Another notable commander was the Field Crown Hetman, Marcin Kazanowski. King Władysław IV, a great supporter of the modernization of the Commonwealth army, proved to be a good tactician, and his innovations in the use of artillery and fortifications based on Western ideas greatly contributed to the eventual Polish-Lithuanian success. He had replaced the old arquebusiers with musketeers, and standardized the Commonwealth artillery (introducing 3- to 6-pounder regimental guns), both to great effect.
Commonwealth's cavalry, including the Winged Hussars, significantly restricted Russian mobility, forcing them to stay in their trenches. In a series of fierce engagements, Commonwealth forces gradually overran the Russian field fortifications, and the siege reached its final stages by late September. On 28 September 1633, Commonwealth forces took the main Russian supply points, and by 4 October the siege had broken.
Shein's army retreated to its main camp, which was in turn surrounded by Commonwealth forces in mid-October. The besieged Russians waited for relief, but none arrived, as Commonwealth and Cossack cavalry had been sent to disrupt the Russian rear. Some historians also cite dissent and internal divisions in the Russian camp as responsible for their inaction and ineffectiveness. (Jasienica blames the Russian warlords, and Parker the foreign mercenaries.) The Tatar invasion threatening the south Russian borderlands was a contributory factor, with many soldiers and boyars from those regions deserting the Russian camp to return to protect their homeland. Some foreign mercenaries also deserted to the Commonwealth side.
Shein began surrender negotiations in January 1634, and by February they were in full swing. The Russians finally signed a surrender treaty on 25 February 1634, and on 1 March they vacated their camp. (Some scholars, such as Rickard and Black, give the date of 1 March for Shein's capitulation.) Under the surrender terms, the Russians had to leave behind most of their artillery but were allowed to retain their banners after a ceremony in which they were laid before King Władysław. They also had to promise not to engage Commonwealth forces for the next three months. Shein's forces numbered around 12,000 at the time of their capitulation, but over 4,000, including most of the foreign contingent, immediately decided to defect to the Commonwealth.