"In September, the Ukrainian military launched Operation Vivaldi. This phased counteroffensive seeks to liberate Ukrainian territory in the eastern part of the country in the direction of Luhansk Oblast.
Thus far, the operation has been a success, with significant territorial gains for the Ukrainian forces.
The Ukrainian army launched a two-pronged assault. Ukrainian forces from the west conducted a feint, drawing Russian reserves and resources, and then the main Ukrainian force struck from the north.
Faced with the threat of encirclement, Russian units pulled back in the direction of Luhansk Oblast. By the end of September, the Ukrainian forces had liberated nearly 69.5 square miles (180 square kilometers) of territory.
Artillery has played a key role in the Ukrainian success…"
link
Armand
goes beyond the straight line.