Russian friend/foe signs in Ukraine: O, V, Z et al.

What are they used for?

They primarily serve as identification friend or foe (IFF) measure to, basically, prevent friendly fire. This is increasingly important when acting against forces that use vastly similar equipment, which is the case for Russian army in Ukraine. Ukrainian army later also developed their distinct signs for the same reasons.

Why are different signs needed? Wouldn't just one suffice?

We don't know. Possibly to make command and control easier with plenty units deployed simultaneously. This likely became more beneficial as different units have been re-deployed to the same areas.

How were they assigned, exactly?

According to evidences it looks like each Russian military district along with Russia-aligned militia in Donbass has been assigned their distinct sign, some of them more than one. Brigades and smaller units seemingly never mixed signs within them, though. Here's the initial assignments on the day 1 of Russian invasion:

• Western military district: in Kharkiv region with occasionally used in Sumy region.
• Eastern military district: , mostly in Kyiv region.
• Central military district: and , mostly in Chernihiv region.
• Southern military district: in the South and Luhansk region, with Crimean units bearing but ostensibly retiring it about the time the invasion started.
• Airborne forces (VDV): in Kyiv region, and in the South.
• Russia-aligned militia (DNR/LNR): and seldom .

Are there any exceptions?

A lot. Implementation has never been particularly meticulous to begin with. For instance, 4th tank division apparently never used any of these signs with very few vehicles for somereason bearing signs of the district they don't even belong to.

As Kyiv offensive failed and units started re-deploying, friend/foe sign usage became pretty much a mess with vehicles often times bearing morethanone sign. appears to be dominating above all. It's unclear if it's a deliberate act or the effect of its instrumental role in the Russian propaganda.

What do they mean anyway?

We don't know. It looks like might be standing for Russian В in Восточный (Eastern) as well as for З in Западный (Western). But then is also used for Southern district units, and there's no clear logic behind and . Chances are there has never been any particular considerations other than simplicity and recognition.

Autumn 2022 update

As war protracted, some districts started rejecting older versions and/or adopting new signs for the reasons not 100% clear:

• Western military district: still bearing with 4th tank division as a notable exception.
• Eastern military district: still bearing .
• Central military district: seems to be retiring older marks in favor of newly adopted .
• Southern military district: still bearing , with still found but virtually retired.
• Airborne forces (VDV): now using , and , often combined as , mostly in the South.
• Russia-aligned militia (DNR/LNR): still bearing and .

Summer 2023 update

• Western military district: started replacing older signs with in early 2023. This didn't seem to last, and was soon replaced with , now a widely adopted standard. 20CAA seems to be using their own along with it.
• Eastern military district: now mostly using .
• Central military district: recently introduced that is now being used along with .
• Southern military district: still bearing , with rarely seen on older equipment.
• Airborne forces (VDV): now also heavily present in the East, still widely using , , and as well as .
• Russia-aligned militia (DNR/LNR): still bearing , and, less often, .