The 'Sumy-Priluki Offensive Operation' was one of the three Soviet operational-level undertakings that together constituted the 'Chernigov-Priluki Strategic Offensive Operation', and was fought by the Voronezh Front against the 4^th Panzerarmee (26 August/30 September 1943).

After the end of the Battle of Kursk resulting from the German 'Zitadelle' offensive, the Soviet high command attempted to capitalise on the Soviet victory which had been achieved. The troops of the Central Front, Voronezh Front and Steppe Front were allotted the task of liberating those parts of Ukraine lying on the left bank of the Dniepr river while advancing on the front between Cherkassy and Poltava, reaching the Dniepr river, crossing this off the march to seize bridgeheads on the river’s right bank and thereby create the conditions for the liberation of the right-bank Ukraine. This grand operation was based on the concept of delivering several powerful strikes using the forces of all three fronts in order to penetrate the German defences and thus to prevent the Germans from consolidating along the banks of the Desna and Dniepr rivers.

At the beginning of the 'Sumy-Priluki Offensive Operation', General Nikolai F. Vatutin’s Voronezh Front had at its disposal General Leytenant Nikandr E. Chibisov’s 38^th Army, General Leytenant Kyrill S. Moskalenko’s 40^th Army, General Leytenant Pavel S. Rybalko’s 3^rd Guards Tank Army, General Leytenant Aleksei S. Zhadov’s 5^th Guards Army (until 6 September), General Leytenant Filipp F. Zhmachenko’s 47^th Army, General Leytenant Sergei G. Trofimenko’s 27^th Army, General Leytenant Konstantin A. Koroteyev’s 52^nd Army, General Leytenant Aleksei I. Zygin’s (from 27 September General Leytenant Ivan V. Galanin’s) 4^th Guards Army, General Leytenant Ivan M. Chistyakov’s 6^th Guards Army, General Leytenant Mikhail Ye. Katukov’s 1^st Tank Army (from 9 September in the Supreme Command Headquarters reserve), the IV Guards Tank Corps, General Leytenant Viktor S. Baranov’s I Guards Cavalry Corps, and General Stepan A. Krasovsky’s 2^nd Air Army. The Voronezh Front totalled 665,500 men in 42 infantry divisions, five airborne divisions, two mechanised corps, seven tank corps, and one separate tank brigade. The front had 493 tanks and self-propelled guns, 12,600 pieces of artillery and mortars, and 520 aircraft.

After the completion of the 'Belgorod-Kharkov Strategic Offensive Operation', better known as 'Polkovodets Rumyantsev', the front’s troops held the line between the Snagost river and Olshany via the east to the east of Sumy, west of Lebedin, east of Gadyach, Akhtyrka and Krasnokutsk.

The task allocated to the Voronezh Front by the Soviet high command’s directive of 22 August was to deliver the main blow with the forces of the 1^st Tank Army, 4^th Guards Army, 6^th Guards Army and 5^th Guards Army on Poltava and Kremenchug, and an auxiliary blow with the forces of 47^th Army, 1^st Army, 27^th Army, II Tank Corps and III Guards Mechanised Corps in the direction of Zenkov and Mirgorod. Thus, the main blow was to be delivered by the left flank of the front troops in order to reach the Dniepr river and seize bridgeheads in the Kremenchug area. The 38^th Army and 40^th Army were to pin the Germans, and the 52^nd Army was in the second echelon of the front’s forces. The time allocated for the preparation of this signally important operation was just four days, and the Soviet effort was posited in the belief that the Germans could not have organised an effective first-line defence for the 'Sumy-Priluki Offensive Operation' was in fact undertaken as what was in effect an extension of the 'Belgorod-Kharkov Strategic Offensive Operation'.

The Soviet forces were opposed by Generaloberst Hermann Hoth’s 4^th Panzerarmee and part of General Otto Wöhler’s 8^th Army of Generalfeldmarschall Erich von Manstein’s Heeresgruppe 'Süd', and these had the air support of Generalfeldmarschall Wolfram Freiherr von Richthofen’s (from 4 September Generaloberst Otto Dessloch’s) Luftflotte IV. At the Soviet operation’s start, these German forces totalled 265,000 men, 700 tanks and assault guns, 2,725 pieces of artillery and mortars, and 400 aircraft. The Germans hoped to slow the Soviet forces with the stubborn defence along several intermediate lines and thus win the time to complete the construction of the 'Ostwall' strategic defensive line along the Dniepr river, and finally stop the Soviet offensive there and prepare for the 1944 campaign.

On 26 August, the Voronezh Front went over to the offensive, swiftly breaking through the Germans' weak forward line. By a time early on 28 August, the Soviets had advanced as much as 18.5 miles (30 km). von Manstein was able to determine the direction of the main attack, however, and a series of counterattacks led to a battle in the Zenkov-Krasnokutsk region, and this stopped the Soviet offensive.

At the same time, in the area to the north, General Konstantin K. Rokossovsky’s Central Front was undertaking its 'Chernigov-Pripyat Offensive Operation', which broke through to the German defences and rapidly advanced toward Konotop, deeply outflanking the left of the German forces opposing the Voronezh Front. Fearing its encirclement, von Manstein pulled back this part of his front and, taking advantage of this, Vatutin ordered the resumption of the Soviet offensive on 2 September. Three days later Soviet forces liberated Sumy and forced the Psel river, but failed to achieve a decisive success in the Zenkov area.

On 6 September, in light of the successes of the Central Front’s forces, the Soviet supreme command revised the operation’s strategic aims: the axis of the main advance was now transferred from the left to the right flank of the Voronezh Front, and thus to the offensive zone of the 38^th Army and 40^th Army. The 3^rd Guards Tank Army and the I Guards Cavalry Corps now created a mobile group with which to check any movement to the north by other elements of Heeresgruppe 'Süd', destroy the defences of the 4^th Panzerarmee with a deep penetration and reach the Dniepr river in the area of Rzhishchev-Kanev. A subsidiary blow was also to be delivered by the 47^th Army, 52^nd Army and 27^th Army on Cherkassy. The task of attacking Poltava was now assigned to General Ivan S. Konev’s Steppe Front, to which the 5^th Guards Army was transferred.

The regrouping of forces was carried out without a pause even as the Soviet offensive continued. Exploiting the successes of the Central Front, the 38^th Army and 40^th Army accelerated the pace of their offensive to a marked degree, and defeated the German groupings near Romny and Priluki, forcing them into a hasty retreat. On 16 September, Romny, Lokhvitsa and Gadyach were liberated, and by this time the front’s auxiliary grouping had finally achieved success, crossing the Vorskla, Psel and Sula rivers. On the front’s left flank, units of the 4^th Guards Army and 6^th Guards Army were unable to achieve victory, and only after the Germans began a general withdrawal did they begin to advance.

Thus, by 16 September, the 4^th Panzerarmee had managed to break through and force its units to withdraw on two axes toward Kiev and Cherkassy. Realising that it was now impossible to hold left-bank Ukraine, von Manstein gave the order for a rapid withdrawal of his main forces behind the Dniepr river as rearguards slowed the Soviet advance. This withdrawal began on 19 September. To maintain pressure of the Germans, Vatutin pushed his front’s mobile group into the battle on 20 September, and the Soviet forces were now advancing some 12.5 to 18.5 miles (20 to 30 km) per day. The 3^rd Guards Tank Army advanced with particular success: Rybalko allocated a strong forward detachment from each of his three tank corps, and these advanced along forest and farmland roads some 25 to 30 miles (40 to 50 km) ahead of the rest of the army without getting involved in combat against German resistance strongpoints.

On 21 September, Soviet troops began to reach the Dniepr river, the first being Rybalko’s tank forces near Kazantsev and Gorodishche. On the same day the advance detachment of the 40^th Army reached the river to the west of Pereyaslav. By the following day these Soviet elements had crossed the Dniepr river using all manner of improvised means, and captured their first small bridgeheads at the start of what developed as the battle for the Bukrin bridgehead. From 22 to 30 September, elements of the front’s forces reached the Dniepr river along the full 185-mile (300-km) length of the front’s sector and crossed this water barrier straight off the march to establish nine bridgeheads on the river’s right bank. On 26 September, the 38^th Army created the Lyutezhsky bridgehead to the north of Kiev. At the same time, the last German forces on the left bank of the Dnieper river near Darnitsa, a suburb of Kiev, were destroyed.

Immediately there began a bloody battle as the Soviets sought to hold and then to expand their bridgeheads. This battle was particularly fierce in the Bukrin bridgehead, where the 'Dniepr Airborne Operation' was undertaken on 24 September with the aim of enlarging it. Carried out with practically no preparation, however, this operation ended in failure. In general, the struggle for bridgeheads was won by the Soviets: the Germans managed to eliminate none of the major bridgeheads, although the retention of these bridgeheads was very costly for the Soviet forces. By 30 September. the 'Sumy-Priluki Offensive Operation' had been completed and the front’s forces received new tasks and a short pause to prepare for their implementation.

In the 'Sumy-Priluki Offensive Operation', the Voronezh Front destroyed five and defeated four German divisions, advanced between 170 and 185 miles (270 and 300 km) as they crossed a large number of rivers, and reached the Dniepr river along a front of 185 miles (300 km) and seized bridgeheads on the river’s right bank. The German defensive arrangements along the Dnieper river line had been effectively destroyed, and this created the conditions required for the liberation of the right-bank Ukraine.

The most unusual aspects of this entire operation were the facts that the undertaking was prepared and implemented without an operational pause, and that strategic reserves were introduced into the battle as they reached the operational area. Another notable feature was the transfer, during the operation’s course, of the main attack from the left wing to the right wing of the front and then at the end to its centre through the use of a tank army in the first echelon when crossing the Dniepr river. The operation’s failures, from the Soviet point of view, included the lack of mobile forces for deep outflankings and pursuits of the German in its earlier stages, which allowed von Manstein first to stop the Soviet offensive, and then more or less successfully to pull back the bulk of his forces across the Dniepr river. Conversely, when Soviet mobile groupings were created in the operation’s second stage, it was these which who ensured the success of the Dniepr river crossings and thwarted the German plan to stop the Soviet forces along the line of the river. The crossing of the Dniepr river had to be undertaken by the very widespread use of improvised means as there were severe backlogs in the front’s rear services and engineering units.

The Soviet losses amounted to 46,293 men killed, missing or taken prisoner, and 131,211 men wounded or taken ill, and the German losses have been estimated as about 130,000 men killed, missing, wounded or taken prisoner.