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Ukraine is Forming Three New Army Corps—Should it Bring Back Divisions Too?

Ukraine’s armed forces have so far blended their Soviet-military tradition with an influx of Western methods and technologies. Time will tell whether that ongoing adaptation leads to the reintroduction of additional higher headquarter units like Kyiv’s new corps that standardize support services to frontline units, or sticks closer to the ad-hoc approach Ukraine’s military relied on in 2022.

Tank from Ukraine's armed forces firing. Image Credit: Creative Commons.

How should Ukraine organize its forces? The most important fighting units in Ukraine’s massive ground war to roll back the Russian invasion are the armed forces’ dozens of brigades of infantry and armor, each of which counts between 1,000 to 4,000 personnel.

Ukraine Corps Strategy

Organizationally, the prominence of the brigade is in line with most 21st-century armies. But what’s unusual is that Ukraine’s brigades aren’t assigned any permanent headquarters in a higher organizational echelon—like divisions, corps, or field armies. Instead, they’re shuffled between Ukraine’s four regional commands, which then undertake to provide vital logistical and combat support. 

This wasn’t always the case. After the dissolution of the Soviet Union, Ukraine’s armed forces inherited 14 divisions as well as three Army Corps HQs (two formed from former Soviet 6th and 8th Tank Armies) which were disbanded in 2004, 2013, and 2015.

The retirement of these large formations, unlikely to maneuver together on the battlefield, probably seemed practical and forward-thinking at the time. And the regional model seemed to work during the first year of Russia’s large-scale invasion, as Ukraine harnessed its secure interior lines of communication to rapidly shuttle its best brigades from one end of the country to the other, slotting in to stamp out operational crises or mount local counter-offensives, then rotating out as they got ground down from combat.

But with Ukraine’s armed forces massively expanded for this big war, some Western and Ukrainian experts think Kyiv might be better served to reintroduce higher HQs to ensure frontline troops are properly supported.

Richard Hooker, former dean of the NATO Defense College, wrote last August that the regional commands: “… lack true battle staffs that can integrate airspace, deep fires, logistics, intelligence, and higher-level command and control.” 

It’s not that nobody is trying to do those things, but rather that’s happening in a more improvised and uncoordinated manner than is ideal, as the more embattled regional commands have to meet the demands of a very horizontally-broad organizational chart. That may work to the detriment of Ukrainian combat units lacking an enduring relationship and continual services from the same higher headquarters.

Hooker argued Ukraine should convert its four territorial commands into Corps, each divided into two or three divisions. He also suggested the formation of a fifth corps of offensive armor and mechanized divisions held in reserve for counter-offensive operations.

Ukraine’s Powerful New “Corps”

Some changes along these lines are now happening, as Ukraine has announced the formation of three new corps. According to The Economist, each will have six frontline combat brigades, some outfitted with newly received Western armored vehicles, that may be employed for its Spring counter-offensive. The six maneuver brigades will doubtlessly be complemented by supporting brigades or battalions of artillery, air defense, combat engineers, and so forth under the control of the Corps HQs.

A corps (also known as “field corps” or “army corps”) is a large military unit ordinarily composed of two or more divisions (each usually with around 15,000 personnel), supported by a Corps HQ and various specialized support units. 

There are of course other military uses of the words ‘corps’ to denote a specialized body of personnel (like the Marine Corps, or the ‘NCO corps’ etc.) but that’s not the usage of corps we’re talking about here.

Corps tend to be less standardized than divisions or brigades, but average 40,000 to 60,000 persons though sizes well above or below aren’t uncommon historically. Multiple corps can be grouped together into an even larger unit known as an army or “field army.”

In practice, Russian “armies” are more comparable to a Western corps in composition, though Russia’s military retains some army corps in their force structure that is smaller than the Western equivalent. They’re generally a specialized regional grouping of brigades or regiments equivalent to or slightly larger than a division. These notably include: 

Those not deployed to Ukraine, incidentally, have been reduced to shadows of their former selves as personnel from their sub-units have been stripped away to fight in Ukraine

An additional advantage of Ukraine’s news corps, compared to regional commands, is that they can shift their areas of responsibility across regional boundaries. However, the new corps still appear to lack the echelon in between corps and brigade: the division, which typically has two-to-four maneuver brigades each and usually numbers 10,000 to 15,000 personnel.

Ukraine and the downsides of horizontal organization

A Ukrainian officer posting by the Twitter handle Tatarigami commented on social media: “We need a larger structure, such as divisions, especially for large offensives. Another benefit is that you get specific people responsible for logistics, communication and synchronization, rather than ambiguous roles and duties that we have right now on that level.”

It is likely that the sheer number of units brigades attached to each regional command limits how effective and attentive it can be. Back in the 1950s, the U.S. Army adopted ‘Pentomic’ divisions, which traded a force structure based on units of three for one organized around units of five. But this resulted in a degradation of quality because commanders simply couldn’t manage the larger number of sub-units as effectively.

Having so many subunits also results in a competition for resources that often favors “rock star” units over those with less glamorous reputations who may get caught in a vicious spiral of failure and heavy losses.

Glenn Grant, a British defense analyst and advisor to Ukraine’s military, wrote that he fears the current structure lends itself to this:  “There are simply too many organizations working separately from each other and even at times in opposition. This creates pockets of “first, second and third “divisions of quality where some units are equipped and trained properly, and others are not… This lack of a common concept encourages organizational arrogance where some parts of the military system are considered better or more important than others and are both treated and act so. This attitude risks sending soldiers and volunteers to their death early because the system has not valued them sufficiently to prepare them properly for the realities of battle.”

Adding a divisional HQ, then, would guarantee a higher-level staff dedicated to providing various services for a smaller number of brigades. That usually includes mid-to-high ranking officers dedicated individually to functional roles: personnel, intelligence, operations and training, and logistics—and often also civil affairs, signals/cyber, and medical. It’s like how corporate leadership often includes functionally tasked CTOs, COOs, and CFOs.

The division would also dispose of support assets reserved for their frontline brigades—typically a brigade/regiment of artillery, and full battalions of other types of support troops.

To be fair, siloing resources this way may make it harder to redistribute them when mass is required. And a downside to more robust support and HQ presence is that this shifts personnel away from frontline roles to support/admin/and logistics jobs, a balance known as teeth-to-tail. The Russian/Soviet tradition favors a high ratio of teeth, while Western militaries emphasize robust logistical tails. 

The teeth-first approach guarantees more bodies and vehicles on the frontline—though they’re also more likely to get ‘spent’ due to casualties and logistical exhaustion. The argument for investing in the tail is that by ensuring frontline troops are better supported, a smaller number can remain effective for longer and with lighter casualties.

Though the new organization may require more support personnel, Hooker argues there may be a larger pool of human resources that can handle many of the non-combat tasks, meaning the reduction to combat troops might not be on a strictly zero-sum basis. 

Grant, though not in favor of a larger ‘tail’, nonetheless argues the Ukrainian Army should induct more civilians to take on support and administration roles, ensuring military personnel are channeled toward functions only they can be trained to perform.

Not everyone agrees that re-introducing larger formations is vital, however. Konrad Muzyka, a Polish defense analyst wrote to me: “Kharkiv Offensive showed [Ukraine’s military] had a flexible approach. They created new tactical-operational commands, which ran 4-5 brigades in their respective Areas of Responsibility (AORs).” 

In other words, creating temporary equivalents of divisions or Corps to execute a highly successful maneuver operation. That might draw from the Soviet doctrine of the Operational Maneuver Group, a temporary grouping of powerful mobile forces created to penetrate deep into enemy lines.

Konrad also pointed out that on the frontline, Ukraine’s army fights side-by-side with other branches of the armed forces like Marines, Territorial Defense Forces, etc.—units that couldn’t ordinarily be inducted into a permanent division or corps-level formation of the Ukrainian Army.

Of course, it’s ultimately up to Ukrainians to decide how their armed forces are best organized. While it has benefitted greatly from western training and advising, there’s also a risk that foreign advisors try to push templates from their ostensibly more modern advanced military culture that may actually be ill-suited to the context and realities of their advisees

Ukraine’s armed forces have so far blended their Soviet-military tradition with an influx of Western methods and technologies. Time will tell whether that ongoing adaptation leads to the reintroduction of additional higher headquarter units like Kyiv’s new corps that standardize support services to frontline units, or sticks closer to the ad-hoc approach Ukraine’s military relied on in 2022.

Sébastien Roblin has written on the technical, historical, and political aspects of international security and conflict for publications including 19FortyFive, Popular Mechanics, The National Interest, MSNBC, CNN,, Inside Unmanned Systems, and War is Boring. He holds a Master’s degree from Georgetown University and served with the Peace Corps in China.  You can follow his articles on Twitter.

Written By

Sebastien Roblin writes on the technical, historical, and political aspects of international security and conflict for publications including the 19FortyFive, The National Interest, NBC News,, and War is Boring. He holds a Master’s degree from Georgetown University and served with the Peace Corps in China.  



  1. Gary Jacobs

    March 31, 2023 at 7:47 pm

    It’s so ironic that the growing pains Ukraine is having [re]organizing a massively expanded military also speaks to how little they were actually preparing to fight Russia, but really just how they were absolutely not a threat to Russia before Russia’s imperialist invasion.

    Putin’s mythical invention of a threat from Ukraine is so transparently bogus it’s bizarre there are so many propagandists still trying to make excuses for this invasion. Especially many of the commenterson this site.

    Putin is getting self fulfilling prophecies left and right. Now Ukraine is a massive threat to Russia’s military.

    NATO has massively expanded its border with Russia now that Finland has joined.

    And all of Russia’s neighbors are massively expanding their militaries. Especially Poland, but others as well.

    Yet Putin knows that NATO is a defensive organization, otherwise he wouldnt have pulled so many troops from Kaliningrad and Russia’s western border to fight in Ukraine.

    btw, On this day on year ago the Russian war effort in Ukraine’s North completely collapsed. The surviving Russian units were forced to abandon Kyiv, Chernihiv, Sumy and Zhytomyr regions. 33,000 square kilometers of Ukrainian soil were liberated within about 48hours.

    The victories were quickly followed by deep sorrow in the formerly occupied cities where many executed men, women and children were found in the streets, especially in Bucha.

    This is a continuation of centuries of Russian atrocities against its neighbors.

  2. 404NotFound

    March 31, 2023 at 9:34 pm

    Ukros are definitely forming raw SS divisions for the final battle of Donbass.

    Russia will send off with a few handy tactical nukes and BYE-BYE ! Hasta la Vista !

  3. 404NotFound

    March 31, 2023 at 9:35 pm

    Ukros are definitely forming raw SS divisions for the final battle of Donbass.

    Russia will send off with a few handy tactical nukes and BYE-BYE ! Hasta la Vista.

    See ya in the next life !

  4. 3L120

    April 1, 2023 at 12:35 am

    The ape tonic Army and its 5 Battlegroups wasn’t around long enough to determine its usefulness. Making divisions can also just add an extra level of command friction to the Corps level, plus make for more Generals. I assume the Brigades have a staff which can interface with Corps level.

  5. Jacksonian Libertarian

    April 1, 2023 at 2:18 am

    “Captains should study tactics, but Generals must study logistics.”

    Logistics is what will determine the outcome of this war.

    The Russians have demonstrated their incompetence at logistics with the 40 mile long convoy that didn’t move for weeks. They have also demonstrated that they can’t fight if more than 100 miles from a train line. In addition, the Russians have already burned through 50% of their prewar materials, to little effect.

    The Ukrainians need to gain the greatest advantage they can from their interior lines, Western support, and efficient logistics. Organizing their forces to more efficiently use the available resources just makes strategic sense. Command staffs that see to the even distribution of resources so that neither men or materials are wasted, will provide the greatest combat power.

    Creating new command organizations on the fly, in the middle of a war will be difficult. Some of the advantages of the larger units will be unrealized as practical experience takes time to develop. Ukraine will need to depend on Western models and advisors to get the best results they can.

    Note: Free markets are the most efficient way to allocate resources. Free markets empower every participant to get what they need. Authoritarian Cultures can’t support free markets because political power negates the “Rule of Law” necessary to secure “Private Property” and encourage free market participation. The 1st World is the 1st World for this reason. Compounding growth is the most powerful force in the Universe, and the foundation of all Strategy.

  6. Jim

    April 1, 2023 at 11:29 am

    The article is a good summary of the pros and cons of various force structure configurations… and how they might be applied to Ukraine.

    The problem for Ukraine is the various examples of force structure change happened in peace after much thought and ability to see how it worked in training exercises.

    Any change to the current force structure has to be done “on the fly” with critical demand @ the front taking precedence.

    There are competing demands… immediate “fill in” on the front versus longer term training which has been going on in various Nato countries.

    Also, there’s an implication this will enhance Ukraine’s fighting ability.

    But, here’s the thing, Ukraine’s military has never carried out a “combined arms maneuver” offensive.

    Both Kharkov & Kherson, while successful to a point, more so in Kharkov than Kherson, did not rely on a sophisticated “combined arms maneuver,” rather, each was fairly simple “straight ahead” action.

    Equivalent to an American football play of handing off the ball to the running back “up the middle.”

    “Combined arms maneuver” is more like a intricate “end around” or “sweep” in football, possibly even with “counter action” motion included… which takes more timing & coordination… more practice to get it right in a game situation… where a successful play gains yards.

    Ukraine’s military defense posture before the war started was static defense behind physical defensive barriers… it has had success. (Although, evidence exists which does suggest Ukraine had ambitions to launch into the Donbas an offensive designed to “run off” eastern Ukrainians with Russian persuasion into “Mother Russia.”

    Reorganizing the Ukraine military from the top down in the middle of the war is highly problematic.

    I suggest this is simply idle talk during the current stalemate @ Bakhmut.

    The resolution of Bakhmut will influence all that follows after it.

    Even President Zelensky has admitted as much.

  7. David Chang

    April 1, 2023 at 3:54 pm

    God bless people in the world.

    Because the casualties of Ukraine soldiers are more than 100,000, and the Ukraine reserves are learning the SBCT tactics of the United States, Ukraine military should adapt with the strategy theory and tactics orders of U.S. military.

    Let Ukraine military adapt with U.S. armored division, and let chaplains teach Ukraine soldiers to trust God, so soldiers would like to keep in the tough battle and pray to God.

    God bless America.

  8. cobo

    April 1, 2023 at 6:03 pm

    Each new day brings world a little closer to Armageddon (at least for Europe) as ukros forces are highly lauded by the ‘international’ media and said to be growing in numbers and strength as the war drags on.

    Meanwhile the UK is sending uranium-based munitions to ukros while US is sending monster M1 panzers, new missiles and smart munitions besides hurling over oodles of dollars.

    So, Russia’s reply must be as simple and direct as possible.

    Remove the covers, dust off the tactical missile bodies and hurl them at ukros and observe biden’s reaction.

    Will Biden hit out at nations in east Asia and thereby turn his ukraine proxy war into a worldwide conflagration (nuclear conflagration that is) and put an end to human civilization.

    Or will Biden step down and hand over his job to Harris.

    Or will Biden and family do the hara-kiri at the family home during a secret private gathering in view of hunter’s growing problem or great humongous scandal that could spell long prison time for Biden family after 2024.

  9. Walker

    April 1, 2023 at 7:59 pm


    Ukraine has reserved around 150,000 troops for its spring offensive equipped with new western arms. The structure they have may be either too small too large or just right depending on how you look at it.

    There, just paraphrases the article in two sentences.

    Hmm, now that I look at it, no wonder the Russian trolls like 404 are foaming at the mouth. It does look a bit scary to the Russians. Speaking of which… 404 are you really so suicidal? Or is this some kind of playing chicken in a VR? Do you really believe saying something so ridiculous will scare anyone?

  10. TheDon

    April 2, 2023 at 7:30 am

    Soon dry season hits.
    McGregor doesnt paint a rosey ukraine position.
    I think the 1945 staff needs some on ground reporting with alternate views.

  11. TMark

    April 2, 2023 at 7:47 am

    Nothing shouts defeat and desperation more than Russian mouthpieces proposing nukes. The neutral half of the globe would immediately shut out Russia for decades. Putin’s generals may not even follow such orders. And Beijing has big-footed Putin out of the idea anyway. Just. Ain’t. Happening.

  12. David Chang

    April 2, 2023 at 9:45 am

    God bless people in the world.

    Isoroku Yamamoto is loyal to the King of Japan, and researches the strategy and tactics of USN, but opposes Japan government ministers and Army declaring war on the United States, which he thinks that Japan will lose.

    Before World War II, famous Japan law and politics scholars and Army officers and government ministers have believed atheism, they encourage people in Japan to invade other country, and declare socialism warfare on the United States, Isoroku Yamamoto opposes the socialism Asia policy of scholars and officers, so Japan Army officers send riflemen to the gate of the Japan Navy Command, aim on the Navy Command, and declare that Isoroku Yamamoto and the Japan Navy are traitors.

    Because of sin, we know that civilian control is a wrong constitution thought, not only police and soldiers are under the command of civilians, but people, police, and soldiers should be humble before God.

    God bless America.

  13. Sofronie the Monk

    April 2, 2023 at 2:53 pm

    Hey, cobo, has this kind of propaganda been approved by Beijing? If I were you, I’d be careful not to upset the master…

    BTW, how come Winnie the Pooh has summoned all the presidents of the former Central Asian Soviet republics to Beijing and Putin just smiled and walked him to his car?

    Perhaps you or 404 can explain more.

  14. dave

    April 3, 2023 at 12:28 am

    What difference does it make the war was decided a year ago. Ukraine loses.

  15. That Guy

    April 3, 2023 at 8:32 am

    Ukraine lost months ago, now hundreds of thousands die for nothing. While billions of US tax payer money is wasted while our streets are filled with homeless and drug addicted. Maybe that money would have been better spent at home, however you might get labeled MAGA for that. Everyone knows that once you’re identified MAGA supporter your political and social life will suffer. You might even lose your job.

  16. froike

    April 3, 2023 at 4:06 pm

    404…Please stop using Drugs! I used to think you were Mentally Inept, but now you have removed all doubt.

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