--- title: "ISW: Operation Vivaldi Disrupted Russia's Encirclement Plan in the Lyman Direction" description: "According to ISW, Operation Vivaldi turned the tide at the front: the Ukrainian Armed Forces reached the Zherebets River, disrupted the Russian encirclement plan, and forced the enemy to suffer heavy losses." date: 2026-10-21T07:21:56.017Z lang: en url: https://xab.info/en/posts/isw-operation-vivaldi-disrupted-encirclement-plan-2026 tags: [ukraine-war, isw, operation-vivaldi, donbas, counteroffensive] author: "Andrey Kosynko" publisher: "XAB.info" --- # ISW: Operation Vivaldi Disrupted Russia's Encirclement Plan in the Lyman Direction ![Burned Russian armored vehicles and a destroyed tank on a ruined road after battles](https://xab.info/media/2026/10/21/isw-operatsiya-vivaldi-sorvala-plan-okruzheniya-2026/isw-operatsiya-vivaldi-sorvala-plan-okruzheniya-2026-1.webp) ## Key Points - According to ISW, Operation Vivaldi allowed the AFU to seize the operational initiative and reach the Zherebets River. - The counter-offensive disrupted the Russian operational encirclement plan via Sviatohirsk and the Barvinkove direction. - Between September 1 and October 16, 2026, Russia lost control of ~122 sq. km, while capturing ~100 sq. km since the beginning of the year, per ISW. - The 144th Motorized Rifle Division of the Russian Federation effectively ceased to exist as an organized formation, according to the institute. According to the Institute for the Study of War (ISW), cited by RBC-Ukraine, Operation Vivaldi and a series of other counter-offensive actions by Ukraine's Defense Forces in 2026 allowed Kyiv to seize the operational initiative along the entire frontline and effectively block the advance of the Russian army. American analysts point out that this specific operation shattered Moscow's plans to capture the Donetsk region. ### The Zherebets River as a New Border According to the ISW report, the counter-offensive thwarted the enemy's attempt to bypass the Ukrainian defense belt from the north and create conditions for its encirclement. The Defense Forces reached the Zherebets River, which made it possible to shorten the frontline and organize defense on more advantageous lines. In such positions, the Ukrainian military can concentrate more infantry in a smaller area, as well as use drones and artillery more effectively. To resume offensive operations in the Lyman direction, Russian troops, according to analysts' estimates, will have to force the Zherebets once again. ### Thwarting the Operational Encirclement Scenario Operation Vivaldi, according to ISW, disrupted the Russian forces' attempt to bypass Lyman from the north through Sviatohirsk and then link up in the Barvinkove area of the Kharkiv region with another grouping advancing from the southwest through the Dobropillia direction. Thus, the Ukrainian counter-offensive thwarted the Russian operational encirclement plan. Now, according to the institute's assessment, Russian troops have to consider the option of a frontal assault east of Sloviansk and Kramatorsk — attacking directly into well-prepared defensive positions, which complicates the advance and increases the cost of the offensive. ### Territorial Changes According to ISW Calculations According to the Institute for the Study of War's calculations, between September 1 and October 16, 2026, Russian troops lost control over an area of about 122 square kilometers. Meanwhile, since the beginning of 2026, according to the same data, they have managed to capture about 100 square kilometers. It was previously reported that Ukraine regained another 101 sq. km of territory as part of Operation Vivaldi in the Donbas. ### Losses of the 144th Motorized Rifle Division During Operation Vivaldi, the 144th Motorized Rifle Division of Russia, according to ISW, suffered such significant losses that it effectively ceased to exist as an organized combat formation. To restore offensive capabilities in the Lyman direction, Moscow will have to rebuild the combat readiness of this formation. ### Growing Burden on Force Generation Rebuilding the division will create an additional burden on the Russian army's force generation system, which, according to analysts, is already facing growing difficulties. Since the summer of 2026, Russia's combat losses have been increasing: over several months, according to estimated figures, the Russian army lost more than 40,000 service members killed and wounded. ## Fact-Check & Sources - [Украинские воины уничтожили большую дивизию РФ во время операции "Вивальди", - ISW](https://www.rbc.ua/ukr/news/ukrayinski-voyini-znishchili-veliku-diviziyu-1792566372.html) - Primary source: ISW report, retold by RBC-Ukraine. All territorial and personnel figures (122 sq. km, 100 sq. km, 40k casualties, 144th division) are cited as ISW estimates; there is no independent confirmation in the provided materials. ## FAQ ### What is Operation Vivaldi? According to ISW, it is a counter-offensive operation by Ukraine's Defense Forces in 2026, during which Ukrainian troops reached the Zherebets River and shortened the frontline. ### What territorial changes does ISW record? According to the institute's calculations, from September 1 to October 16, 2026, Russian forces lost control of about 122 sq. km and captured about 100 sq. km since the beginning of 2026. ### What happened to the Russian 144th Motorized Rifle Division? According to ISW, during Operation Vivaldi, the division suffered such losses that it effectively ceased to exist as an organized combat formation.