Ukraine's Operation Vivaldi: Incremental Tactics and Artillery Break Russian Bridgehead in Donetsk

Key points

• The 3rd Army Corps, led by Brig. Gen. Andriy Biletsky, reclaimed 176 sq km of territory by late September 2026, pushing back Russian 20th and 25th Combined Arms Armies.
• Tactics focused on 'geometric interdiction' and positional pressure, advancing incrementally rather than seeking a single decisive breakthrough, contrasting with the failed 2023 counteroffensive in Zaporizhzhia.
• Artillery played a critical role, with the 52nd Separate Artillery Brigade maintaining continuous fire to prevent Russian reinforcements, destroying over 20 guns and two Buk air defense systems.
• Unmanned systems were central, with ground robots clearing mines, delivering supplies, and evacuating casualties; the corps was the first to air-deploy ground robots behind enemy lines.
• ISW assessed that the operation broke the northern arm of Russia's pincer plan to encircle Sloviansk and Kramatorsk, resulting in a net Russian territorial loss of 81 sq km in September.

Background

Operation Vivaldi followed the failed 2023 Ukrainian counteroffensive in Zaporizhzhia, which stalled after 10 km due to minefields and lack of air support. Recent archive reports from September 2026 indicated the offensive was progressing in phases, with the third phase concluding in late September after reclaiming 51 sq km and capturing 250 prisoners. The operation was officially disclosed by Kyiv on September 15, 2026, after months of near-silent execution.

How outlets are covering it

Euromaidan Press emphasizes the strategic shift from 'big thinking' to 'small thinking,' highlighting the role of US Army officers in analyzing the success as a rejection of traditional maneuver warfare. Business Insider focuses on the continued relevance of artillery, noting that heavy fire was essential to holding gains and preventing Russian counterattacks, despite the dominance of drones. Kyiv Post provides a broader strategic view, noting that while Vivaldi succeeded, Ukraine faces risks from Washington's pressure to stop striking Russian refineries, which could undermine the economic pressure that supported the military success. All sources agree on the territorial gains but differ on the primary driver: Euromaidan Press cites tactical innovation, Business Insider cites artillery, and Kyiv Post cites the integration of multiple command structures.

Why it matters

The success of Operation Vivaldi demonstrates that Ukraine can reverse Russian advances through incremental, technology-integrated tactics rather than large-scale armored breakthroughs. It validates the effectiveness of combining artillery, drones, and ground robots in a unified command structure. However, the operation's success is now threatened by diplomatic shifts in Washington, where pressure to halt strikes on Russian energy infrastructure could reduce the economic strain on Russia that has supported Ukrainian battlefield gains. This highlights the interdependence of military and diplomatic strategies in the conflict.

What to watch

The 3rd Army Corps has indicated that Operation Vivaldi is not over, with a fourth phase potentially underway. ISW believes the third phase is currently active. Ukraine is expected to continue pressure in the southeast against the Russian 29th Combined Arms Army. However, the future of the offensive depends on whether Washington maintains support for Ukrainian strikes on Russian refineries, as any cessation could allow Russia to rebuild its war economy and reinforce its positions in the Donbas.