Lessons of war: every war is different, yet the basics remain the same - isolate and destroy. There is a hard way and their is an easier way to defeat your opponent. There is the art of war, and their is the wall of reality. The Ukrainians have shown more creativity and initiative in the art of war - likely through the eyes of their backers. The Russians started the war with a lot of imagination and initiative, but hit the wall of reality that splitting your forces is the best way to have them devoured - the wall of reality. They were forced to recoil, and the Ukrainians simply followed their retreat out of Kherson, Sumy, Kiev, and Kharkov Oblasts. The Ukrainian advance stooped just west of the Oskil River when Russian contraction allowed them to solidify defensive lines. The Ukrainians then made several ill-advised offensives for the flanks of the destroyed city of Bakhmut, which unnecessarily ate man power, resources, and time. They are currently attempting to capture Tokmak as a gateway to the Azoz Sea coast - which is mired in failure. The time may be ripe for a massive Russian offensive to decisively end the war.
LESSIONS OF WAR
One of the biggest lessons of this war has been flanking major concentrations of enemy troops without sufficient distance between the parties is a recipe for loss. Loss can be in momentum, in troops, in equipment, in morale and in time - all enemies of a successful military campaign. We have witnessed this from both sides in this war. Whether its the endless Russian quagmires of Avdiivka and Marinka, or the Ukrainian quagmires of Bakhmut and Zaporizhia. Limiting yourself to a flanking that exposes your forces to the maximum range effect of the enemies artillery support, and mining, guarantees that your efforts will result in stalemate at best. This has become the reoccurring theme of the Ukrainian War. So lesson one is flanking pincers must bypass major troop concentrations - not engage them. That's Blitzkrieg 101. The strategic aim to cut off supply to the enemy BEFORE engaging them in an attrition battle.
Lesson number two: piecemealing forces is a recipe for disaster. We witnessed the Russians commit this terrible strategy when they invaded Ukraine. It ended up in a loss of: momentum; troops; equipment, morale and time. The Ukrainians were able to survive and rebuild. What has happened since is piecemeal attacks by both sides, with the exceptions of Bakhmut and Mariupol, which have resulted in mass casualties with no significant progress - near stalemate in other words. Wars are not won on offensives conducted by battalion or less groups, yet that is what has been happening along almost all parts of the front by both sides - resulting in nothing but casualties and losses in equipment.
Lesson three: concentrated, long range attacks against strategically imperative targets are highly effective. The Ukrainians essentially made the Russian positions in Kherson Oblast untenable when they rendered the Kherson bridge unusable. The Russians have been terrible at this - for some reason. For example there are only two Ukrainian rail bridges crossing the Dnieper River: the Amursky Bridge in Dnipro; and the Petrivskiy Bridge in Kiev. Both those bridges still stand and allow Ukraine to transfer Western arms and ammunition to its forces in the most efficient way possible, rail, given the size of the country. The hydro dam bridges that dot the Dnieper remain untouched - ditto for the car bridges. This one lesson appears to be completely lost on the Russian leadership, and has been a major strategic mistake harming Russian forces on a daily basis.
Lesson four: minefields stop troops and equipment from moving - Zaporiozhia for example. They can be used in an offensive or defensive posture. They can stop troops from advancing, and they can stop troops from retreating. Essentially, Russian mobile mine-laying units, like the modern ISDM Zemledelive, can be paired with armored formations to fix enemy flanking forces in place while bypassing them to greater depths. In a Blitzkrieg-like offensive, the ability to instantly trap the enemy in strongholds while on the move opens the doors to large advances. It is a combined-arms operation that hasn't been utilized well by the Russians.
Frankly, the lessons of this war could be covered in a very thick book, and a simple blog can hardly cover it all. The bottom-line is the Russians are about to initiate a very large offensive of their own, and the only question is where and how.
Given the lesson the Ukrainians taught the Russians in Kherson, which the Russians should have foreseen, any coming offensive must first sever the artery of supply. Without food, ammunition, and fuel a modern army cannot survive for more than weeks, so cutting supply is the first priority. To that end the Russians must first conduct a massive airstrike on Ukraine's most capable air defences - the German and American AD. Simultaneously, the Russians must destroy the railway bridges over the Dnieper so that Ukraine can no longer supply its forces with mass railway movements - that's two bridges. With major air defences destroyed, Russian strategic bombers focus on destroying Ukrainian artillery regiments in the Sumy/Kharhov regions.
Russian airborne forces conduct mass drops along the river just west of Poltava. Their objective is to secure the river crossing (no bridges needed) for the coming armored and mechanized infantry forces that will surround Poltava and move on to Kremenchuk and Dnipro. The Russian Army will use two centres for the start of their operation: Kursk and Belgorod. The Kursk group will flank the city of Sumy at a distance, isolating it as it goes with mobile mining, and proceed to the crossing points the airborne have secured. They will then isolate Poltava in the same fashion as Sumy, and proceed to the Dnieper. The second grouping, from Belgorod, will also flank Kharkov at distance, isolating it in the same fashion with mobile mining, then move to the eastern part of Poltava, isolating it, and meeting up with the Kursk grouping at Dnipro. It is critical that the route of the advance is not too narrow, avoids rivers requiring bridges, and is open enough for armored/mechanized warfare. No forests, no rivers, no cities and as few tree lines as possible.
Having secured its positions in Phase Two, the Ukrainian forces in Eastern Ukraine will be trapped and without supply. The Ukrainian forces in these areas will have no choice but to surrender. They won't do so immediately, but the plight of the troops and the fury in Kiev will likely force the Ukrainian military/government's hand. A show of successful force in a decisive manner, will likely quiet the war drums beating in places like Poland, etc. However, even if this offensive succeeds, and it does not quiet the warmongers, it will leave Russia in the position of controlling all of Eastern Ukraine, and opens the doorway to Odessa. Time will tell what path the Russian military/government choose, but whatever they choose must incorporate the lessons of this war, otherwise the fingers must be pointed inward.