A Collection of Tactical Heuristics

[Iconoclast]

Hello All,

while reading Peter's Beda Fomm AAR, which I greatly enjoyed, one sentence struck me

Original by John Connor:

But what if they come over those 'hills' and down onto the positions? I could put units on the hills too, but that would spoil the surprise. It all sounds a bit too tactical really. As usual playing this game and having no military experience, I really haven't a clue......

I am not proposing a solution to this specific problem. But it reminded me that there are many different memory aids, and "heuristics" out there, that are supposed to help you to remember what has been tought to you, while being under stress. OCOKA is one example. Another one would be a phrase that I got drilled into my head during basic training: "Wirking vor Deckung", (loosley: "Firepower trumps cover"). The list goes on and on. I thought I collect a few useful ones here, not word by word, but add enough context to them as needed. I will edit the list during the next weeks to add more, since my documents are currently not available, since I am moving( to DC by the way, if anyone cares to have a tea, let me know.)

These heuristics here are not meant to be in-game tactics, nor universally applicable. But they are supposed to be a guideline once things heat up, and you feel like being overwhelmed by choices. To think that these are 'rules' is probably the worst approach you can take.

Apart from the military aspect, heuristics helped me a lot in exams at university too. I tended to be one of those that tried to reinvent the wheel, instead of reminding myself that these exams have been written with the intention to check you for knowledge, not for innovation. To take a breath and remind me of the basics, has helped a lot. This is a valid analogie to the military usage in my eyes.

Feel free to move the thread, critique, or add some own. I might sort them during the days too.

Tactical Heuristics

Centre of Gravity/Schwerpunkt: Always have one. Always. Create one through reserves, Combat Support, logistics, and space (by assigning a smaller AO to worry about). In the offense, put the Schwerpunkt, where the enemy shows weakness, and the terrain allows it.

Reserves: Always have one. Always. The golden Rule is the '1/3rd Rule'. 1/3rd of your force is the reserve, the other two thirds are 'abreast'. in case you don't know which force to take, choose the stronger over the weaker, the faster over the slower.

Recon: Harder to implement in CO, but: The less you know, the broader you deploy recon. Once intel comes in, let them converge onto the Areas of interests. Maintain contact once it is established, don't loose it.

Far-away/close Objectives: Is your Objective far away from the LD, Organize your Forces narrow and deep. That way, the follow-up units can easier protect the flanks of the main force, so they don't end up cut off. Vica Versa, organize your force broad and 'flat' when having a close objective, to bring more firepower to bear.

Combined Arms: Mix Tank and MechInf in unclear situations, Urban Operations or very close terrain. Attack with MechInf abreast to seize gaps, crossing points, or other kinds of choke points. Attack with tanks abreast to fight in open terrain.

Planning Cycle: Spend max 1/3rd of your time planning, the other 2/3rd are meant for your subordinates to implement the orders. (e.g.: Your got 3 hrs to seize village with your Coy, after an hr your brief your Plt Ldrs, so they now have the remaining two hours.)

Infantry forces the enemy into close combat: Don't let them catch you in the open. Don't put units directly at forest lines, or villages, pull them back into the depth of these terrain features, and force the enemy to close in. An often overlooked means to achive that, is the 'reverse ridgeline defence'.

AirborneOps: (relevant for Gary Grigsby's, or OCS Series) Only conduct if you can't reach the same objective in the same time frame with conventional ground forces.

The Persuit: Once the enemy disengages, do not loose contact. Chase him. This should become P1 in these situations, get into melee with him, give him no chance of getting into a steady defence again.

Always cover your obstacles: To see a few tanks run into a minefield is not nice, to see the whole company getting shredded into pieces while trying to clear a breach, and being under accurate direct and indirect fire, is even worse.

Costs of opportunity: Use your units in the role they excel, taking into account what akes them special to have proper 'economy of force'. Example: in Flashpoint: Campaigns, people tend to throw out their FASCAM at the first best occaision, usually an intersection on the Avenue of Approach. The enemy runs into it, looses a few units, and breaches it. Instead, normal Minesystems could have provided the same field ("in front of the enemy"), while FASCAM fields can throw mines between main and follow-up forces. Thats what makes them special, to lock these two bodies away from each other. FASCAM has a higher value in that role.

Starting point of every plan is the enemy situation: There is a reason why every Briefing starts with the '1A', the enemy situation.It is him who dictates what is necessary, not what you can/could do. Do not waste resources only because you have them.

Distance of Artilley: The rule of thumb is, one 1/3rd of your artillery's range to the action, two thirds beyond it. Artilley has not been developed to shoot 20+ kilometer far, so the enemy takes a step back and is out of harms way. Make sure your Artillery can 'accompany' your assault with fire support in the offence, and attrite the enemy early on in the defence.

Fire and Maneuver, Maneuver and Fire (Credit to Baloon): Both goes hand in hand. Never do the one, without the other. If direct fire can not be provided, substitute with indirect fire (happens often during disengagements)

FIX-FLANK-DESTROY-REPEAT Says it all. Remember that combat is not linear. Combat means to constantly outmanouver the enemy, the popular "hammer and anvil" being the most common example. This also applies for defense!

Fire can only contest temporarily. If you want to hold an area, you need boots on the ground.

If you want to seize an area, better do it today than tomorrow. Imagine the following: an eny Tnk Bn is moving to seize an currently unoccupied crossing point. He will arrive in 10. You have the chance to either send a Tnk Coy that arrives there in 5, or wait for the rest of the Bn and arrive there in 15. Right, send in the Tank Coy. Even if it is just a platoon, send them in.

Screen the areas in which an enemy advancement is unlikely. Use weak forces, not meant to hold, but just to give you eyes on an area, to free up proper combat units deployment where you seek to force the issue.

If you do not want to be seen, maybe because you want to infiltrate, or you are in the role of a small unit; move like the water flows. Use valleys.


I will come back to the list in a few days to add a few more. Thats what came up while writing that down in 20 minutes.

Cheers,

A

 

[Dave 'Arjuna' O'Connor]

Great stuff. Many thanks.

 

[DerGrenadier]

Great idea. Already loving it.

 

[Ramses]

Great tactics 101. Thanks for your insights en please do come back with more.

 

[Doolan]

A truly fantastic summary, Iconoclast! Although I have a degree in Military History, I have never served in the Armed Forces, so these are rules I have mostly had to either infer, or study in long and awkward manuals — FM 3-0, Operations, springs to mind as one of the most relevant for the CommOps2 scale, but it is a long and more than a bit arcane read. I truly appreciate the time you are taking to spell them out as bullet points for rookies like me, and I look forward to learning more from your experience.

Now, I might be completely off in suggesting this one, as it might be outside the scale of what you intended, or even implied in the definition of the 1/3 reserve, but, how about bounding overwatch? Although mostly quoted for platoon-level tactics, I find it useful at battalion level as well.

Essentially, always keep one half of the forces dedicated to an assault on overwatch while the other half 'bounds' to a set forward position: the first half, performing the overwatch, provides covering fire, keeps a clear LOS on the enemy positions at all times, prevents your assault force from being cut off, and is free to react to any surprises the enemy might have in store. Plus, by alternating the overwatch / assault roles, your forces have twice the time to rest and reorg, thus always keeping them relatively fresh.

I hope it was not a silly or overly obvious thing to say in this context!

Also, any general heuristics on the use of artillery support?

Thanks again, Iconoclast, you are a star!

(Edited because it was not too obvious that "FM 3-0" was actually a link to the publication, in case anyone is interested. The forum seems most inconspicuous in its formatting of links, at least on my end!)

 

[Kurt]

Hi, back in the day we used to call that tactic 'leapfrogging' though we only used it at platoon or lower level. I guess it would be useful at battalion level for VolksGrenadier divisions as there regiments only have two infantry battalions instead of the recommended three. Sound tactical advice by ICONOCLAST

 

[Dave 'Arjuna' O'Connor]

In fact the leapfrogging tactic was used by the British Armoured divisions late in the war where it divided its Bns into Groups of one armoured Bn and one mot/mech inf Bn. It would commit one group or a pair of groups to secure an objective along the main axis. Once it had secured that objective, it would punch through another group or pair of groups to secure the next objective along the axis and so on.

The American Army often used tri structures and hence it's options were limited in terms of keeping a reserve to either one third of the force or two thirds. The Brits used a square structure and hence could have either a quarter, half or three quarters in the reserve, which had a bit more flexibility.

As Iconoclast says don't get fixated on the rule. Understand the thrust of what it is saying and apply it always with the situation and mission in mind. It may make perfect sense in some cases to have only a thin screen forward and the bulk of your force in reserve. And there may be times when there is no option but to commit all your force and have no reserve. Though I would rarely counsel the latter.

 

[Doolan]

Great info there! Thanks, Dave and Kurt

And aye, I have never used leapfrogging as gospel — sometimes it is not practical, and there is also the situation in which your OOB grants you the luxury of an ideal overwatch element, such as a heavy weapons company, that you want to keep in position most of the time.

This sort of begs the question... Is platoon-level leapfrogging in some way implied in the game code? Say, if I assault a given position with a single company, will it fire at, and suppress the enemy as it advances, reflecting leapfrogging performed by its platoons? Or do we need to instruct another separate unit to suppress the target? Not trying to hijack or derail the thread, just wondering how this would actually work in-game.

Thanks again!

 

[Kurt]

Interesting point there Doolan, well trained infantry without heavy weapon support would automatically use fire and maneuver 'leapfrogging' in an assault making use of their organic squad machine guns and rifle fire. The alternating moving element would be running like crazy without firing searching for the next piece of cover ahead, then diving down behind that cover as one and emerging around the side of cover to provide cover fire for the other team to break cover as one and run like crazy etc. In the absence of cover smoke grenades would be used. Russian troops and poorly trained infantry may just surge forward together screaming and providing nice targets for calm defenders.

 

[john connor]

Very interesting and useful precepts, Iconoclast. Thanks. I feel like I don't do anything that you talk about there, but it all sounds very sound and inspiring. I suppose I do try to keep a reserve, and the Beda Fomm scenario is rare in allowing you to do that, whereas mostly I've found playing CO scenarios that you're really pushed to find a reserve because there is so much you need to do with so few units.

I'm not at all sure how you would (practically) do something like 'bounding overwatch' or 'leapfrogging' at this level of command. It would involve what - direct fire orders to the overwatching company, move orders to another company (with one in reserve)? I've always imagined that when they advance on an order given at Bn level (as I usually so) then all that is taken care of (abstractly). Because I hardly ever use the direct fire cross, partly because it seems absurd to direct an entire company to fire on something. And then add in the delay in getting the order over. It would be tricky to try, I think, at Bn/company level in this game. No?

Peter

 

[Bullman]

+1 That is a fantastic read with excellent use of examples. A practical modern Sun Tzu Art of War without the mystical metaphors.

 

[Doolan]

Very interesting and useful precepts, Iconoclast. Thanks. I feel like I don't do anything that you talk about there, but it all sounds very sound and inspiring. I suppose I do try to keep a reserve, and the Beda Fomm scenario is rare in allowing you to do that, whereas mostly I've found playing CO scenarios that you're really pushed to find a reserve because there is so much you need to do with so few units.

I'm not at all sure how you would (practically) do something like 'bounding overwatch' or 'leapfrogging' at this level of command. It would involve what - direct fire orders to the overwatching company, move orders to another company (with one in reserve)? I've always imagined that when they advance on an order given at Bn level (as I usually so) then all that is taken care of (abstractly). Because I hardly ever use the direct fire cross, partly because it seems absurd to direct an entire company to fire on something. And then add in the delay in getting the order over. It would be tricky to try, I think, at Bn/company level in this game. No?

Peter

Hey Peter!

Agreed, that is why I said the concept typically reminds us of platoon-level engagements (bounding overwatch was sort of the bread and butter of Combat Mission, for example) and asked whether it actually was abstracted in the regular "attack" order in Command Ops 2 when you assault with a single company "counter".

As for making it happen in multiple-unit assaults (let us assume two battalions, although it works with pretty much anything) I have so far done it in the couple scenarios I have played, going more or less like this:

You are facing a well dug-in opponent, there is some defensible terrain nearby — say, a ridge or hill. You order a battalion (or whatever you have around, your budget may vary) to defend that terrain in a formation that brings the most guns to bear and with the desired facing. Once it reaches the spot, it will begin raining fire on the nearest unit it considers a threat, that being the dudes you want to beat over the head. The other battalion (or whatever is left in your bag) is ordered to assault in successive lines, with the advantage of having the enemy units pinned down.

Once (if!) the assault succeeds, you let the assaulting battalion deploy and catch their breath in the terrain formerly defended by the enemy, covering the ground ahead of it, while you order the next assault with the well-rested battalion at the back. Rinse and repeat. In ideal conditions you are even saving time in terms of order delay, since you can tell the overwatch battalion to start packing their luggage while the assaulting battalion is still opening their picnic baskets and learning the local lingo.

And yes, the plan often goes pear-shaped, but I have had much simpler plans fail too, so I think I, and not the plan itself, might be to blame for most of the blunders of my little AI men.

Of course, the ideal situations for it (some terrain advantage near the enemy positions, next enemy position within small arms range of the first, etc.) do not always present themselves, but I guess that is why Dave was suggesting a degree of flexibility in these things.

Also, bear in mind I might very well be mistaken in my use of the terminology — I do not know if "bounding overwatch" is something reserved for the platoon-level-or-under tactic, and the scenario I described above would have a different name, so please bear with me if I said something too nonsensical

Cheers!

 

[Doolan]

Russian troops and poorly trained infantry may just surge forward together screaming and providing nice targets for calm defenders.

I suppose the idea is making the defenders' calmness run out before their targets run out, then

And aye, after reading your comments, I suppose this is somewhat reflected in-game just by making more experienced units better at assaulting stuff. My doubt remains whether a single company "counter" assaulting (that is, making the AI unable to choose a reserve, as it only has that one unit to play with) actually fires at and suppresses the enemy (at a reduced rate compared to firing from a stationary position) as it advances, to account for one of its platoons covering the other two.

Still, as much as I love discussing this (and learning from your comments!), I cannot shake the feeling that we are giving Iconoclast one hell of a job pruning his thread for actual tactical heuristics... Sorry Iconoclast, the momentum carried us!

 

[Iconoclast]

Original by Doolan

Now, I might be completely off in suggesting this one, as it might be outside the scale of what you intended, or even implied in the definition of the 1/3 reserve, but...

As for the scale, I have no real restrictions. I should probably better distinguish between 'heuristics', 'SOP', and 'tactics'.
I won't give you the wiki definition of heuristic: In this context, a heuristic is supposed to solve a problem, that seems like a dilemma while being under time pressure, or to fight your own indeciciveness(e.g. maintain contact Vs. resting). I know that I applied that myself loosley (close/far away Obj for example, that is not a dilemma, more of an SOP) but I thought some of them are interesting anyway. They are also written as rules, since these are easier to memorize than recommendations.

Standing Operating Procedure (SOP), my attempt to translate Kampfweise, is not a dilemma, nor option. It is a single answer to a single question. For example a tanker who encounters another MBT won't ponder about the question to 'load, or not to load' KE ammo. He will just do it, because that's his tool, his answer, to fight another MBT, the question. If he has no KE....well, then he's screwed. @Kurt used the word 'automatically' to describe SOPs in his post:

Original by Kurt

well trained infantry without heavy weapon support would automatically use fire and maneuver 'leapfrogging' in an assault making use of their organic squad machine guns and rifle fire.

Tactical is, a rational plan to win a single military engagement under consideration of the principles of war. (kind of a more narrow Clausewitz definition with a little "+"). Tactic, beeing the art of applying these principles, having the same relation to the single 'plan' as 'painting' has to the single 'picture'.

hence, I would not describe leapfrogging during platoon-level assaults, or during the crossing of clearances as 'tactic', nor as heuristic, but as SOP, whereas the decision on higher level (scale is importand here) to set up an intermidiate Obj to allow one Coy to reorganize while the other proceeds to assault requires a tactical decision (in the narrower sense), taking into account terrain, durability of the units involved, time schedule etc.

I hope that makes sense, any critique on the conceptual level is always welcome. I do not claim that this is absolutely correct. But it should serve as a working definition. Boundries are certainly still blurry.

Original by Doolan

how about bounding overwatch? Although mostly quoted for platoon-level tactics, I find it useful at battalion level as well.

Good point. I have transformed your comment into an heuristic, that applies to pretty much all levels of command. I should have remembered that in the first place. Thanks! The bounding/travelling overwatch is a symptom of the same 'tactical principle, now harnessed in your heuristic. I have edited the list.

Original by Doolan:

Also, any general heuristics on the use of artillery support?

I added one. I will search my documents for more once they are here.

original by Doolan

I hope it was not a silly or overly obvious thing to say in this context!

No, absolutely not.

Original by Peter

I suppose I do try to keep a reserve, and the Beda Fomm scenario is rare in allowing you to do that, whereas mostly I've found playing CO scenarios that you're really pushed to find a reserve because there is so much you need to do with so few units.

And that's what I like about the game: it puts you in the shoes of historical military leaders with all pros and cons (including command battleworn Volksgrenadiers in the Ardennes '44). As Dave said, these are guidelines. That's it.

Original by Bullman

A practical modern Sun Tzu Art of War without the mystical metaphors.

That is probably the most heartwarming compliment I got in my life

Doolan

Still, as much as I love discussing this (and learning from your comments!), I cannot shake the feeling that we are giving Iconoclast one hell of a job pruning his thread for actual tactical heuristics... Sorry Iconoclast, the momentum carried us!

No problem at all. I amend the initial list anyway, so comment and discuss here as much you want. I enjoy reading all your thoughts.

 

[Dave 'Arjuna' O'Connor]

I would like to throw a bone into the sandpit of this discussion by stating an opinion on the definition between tactics and strategy that seems to dog a lot of these types of discussions. One of the things that I have learnt from all the work I have done on developing AI is that there is no real difference between these two. They are both designed to provide a solution to a problem. If there is any difference it's one of scale. People tend to think of strategy applying to higher levels of command and tactics to lower levels. What one person sees as higher in one context, another sees as lower in another context.

Back in 1995 when Paul and I sat down to design our engine I was armed with a swag of doctrinal pamphlets that I had acquired from my time in the military. The best brains of the time had tried to craft a framework and provide definitions. It was written with the Australian Defence Forces in mind and so strategy was at the Brigade level and tactics the domain of the company and Battalions sort of swam the divide depending on the circumstance. An American Division or Corps commander would have chuckled mildly as he referred to all that as "tactics".

Thankfully I knew of this from my study of military history which was broader than just the 'Australian' variety. I originally tried to pigeon hole things into one category or the other while at the same time trying to create a scalable decision making engine. The more I focused on the latter the more I cam e to realise that if there were any differences between these two it was purely semantics. I tend to now use the terms tactical and strategic to describe a scale of operations rather than a process. The process is really the same with perhaps a tendency to use automatic drills or SOPs at the lower more tactical end where time constraints do not allow for in depth analysis.

Anyway that's my tuppence worth for today.

 

[Daz]

This is an extract from a website that helped me tremendously with my games:

(3) ARTILLERY-TANK COOPERATION

Artillery support is of decisive importance for the preparation and the successful conduct of a tank attack. A unified command for the entire artillery controls the artillery fire as long as the infantry and tank units are fighting on the same line. When the tanks break through the enemy forward defense lines, the self-propelled artillery or any other artillery battalion designated for the support of the tank unit is placed under the command of the tank unit commander.

The Germans believe that the artillery fire must not check the momentum of the attack. Consequently the heaviest fire must fall well ahead of the tanks or outside their sector.

The mission of the artillery preparation before the attack is to destroy, or at least neutralize, the opponent's antitank defense in the area between the line of contact and the regimental reserve line. Continuous counterbattery fire prevents the enemy from shelling the tank assembly area and from breaking up the preparation of the tank attack.

The artillery has the following missions before the tank attack:

Counterbattery fire on enemy artillery located in positions which command the ground over which the tank attack is to be made.

Concentrations on enemy tanks in assembly areas.

Harassing fire on all areas in which the antitank units are located or suspected. Fire is heaviest on areas in which tanks cannot operate but from which they can be engaged effectively.

Adjusting fire with high explosives on probably enemy observation posts commanding the sector to be attacked. These observation posts are blinded with smoke as soon as the attack begins.

Experience has taught the Germans that the flanks of a tank attack are vulnerable. Therefore they assign to the artillery and the rocket projector units the task of protecting flanks by barrages using high explosives and smoke shells.

The artillery has the following missions during the tank attack:

Counterbattery fire.

Blinding enemy observation posts.

As the attack progresses, engaging successive lines of antitank defense, especially areas to the rear and flanks of the sector attacked.

Screening the flanks of the attack with smoke and neutralizing the enemy's infantry and rear areas.

Delaying the movement and deployment of enemy reserves,, particularly tanks.

The Germans stress that this wide variety of tasks must not lead to the wholesale dispersal of effort. The main task of the artillery is at all times the destruction of the enemy's antitank weapons, tanks, and artillery.

Liaison between artillery and tanks during the attack is established by the commanding officers and the artillery liaison group, which normally moves with the first wave. Artillery forward observers, if possible in armored observation posts, ride with the most forward elements. A German field expedient is for the tank unit to take along a forward observer in one of it's tanks. It often happens that the tankman himself has to take over the observation of the artillery. He himself can request fire and shift concentrations when the situation requires such changes.

Here is the link to the website:
http://etloh.8m.com/strategy/offense.html

 

[BigDuke66]

Excellent thread!

 

[GoodGuy]

This is an extract from a website that helped me tremendously with my games:

The mission of the artillery preparation before the attack is to destroy, or at least neutralize, the opponent's antitank defense in the area between the line of contact and the regimental reserve line.

Yes, but even mere disruption was also seen as successful outcome with such missions. In practice, all sides figured that prep fire often did not destroy/neutralize AT capabilities, as infantry could hide in strongpoints, trenches or even foxholes, which all offered some level of protection, so that usually -even after a really big/long prep fire- a sufficient amount of troops, using man-portable AT weapons, hollow-charges or bundled grenades, could be found to keep up AT capabilities, even after AT guns had been knocked out. Even early in the war, with AT rifles and early (small) Panzerfaust weapons, it became obvious quickly, that prep fire would rather "soften" enemy targets than destroy/annihilate them, well - with few exceptions.

In the Ardennes, though, the German prep fire focused mostly on the first lines. Rear lines were not covered, for the most part, if I am not mistaken. When the offensive started, the ammo consumption caused by the prep fire was so high, that ammo had to be rationed in artillery units way south of the theater of operations, so that many of these units were not allowed to fire more than 7 shells a day (!).

Continuous counterbattery fire prevents the enemy from shelling the tank assembly area and from breaking up the preparation of the tank attack.

Yup. The German Army employed quite a number of trucks with sound detecting devices used to locate Russian artillery positions, and became quite successful at pin-pointing a fair number of them, eventually.

Blinding enemy observation posts.

Correct. Btw, German aerial observation deterioriated severly in late 1942, so that they depended on recon units carrying out missions on the ground. Before the Russian pincer attack around Stalingrad, they were pretty much blind to what the Russians had gathered on the other side of the river, as aerial recon was either insufficient, or even partially non-existent, while the Russians started to rule the skies and provide sufficient aerial observation, just like the Western Allies.

Liaison between artillery and tanks during the attack is established by the commanding officers and the artillery liaison group, which normally moves with the first wave. Artillery forward observers, if possible in armored observation posts, ride with the most forward elements.

The armored observation posts were usually fast (up to 90 km/h) armored cars with retractable observation devices and long antennas and medium or long-range radio devices for better range, or - when attached to an infantry unit, a single forward observer carrying a radio pack on the back was used, where then the signal platoon's radio truck was vital in relaying the observer's information to the arty unit.

Interesting website

 

[Daz]

Thanks GoodGuy.
Your post was a very interesting and informative read as well.

I have just bought a book Called "Bracketing the Enemy", which is about American forward artillery observers during WW2, to read on my vacation in a few weeks time.

Can you recommend any books that focus on German Artillery during the war?

 

[GoodGuy]

Thanks GoodGuy.
Your post was a very interesting and informative read as well.

I have just bought a book Called "Bracketing the Enemy", which is about American forward artillery observers during WW2, to read on my vacation in a few weeks time.

Can you recommend any books that focus on German Artillery during the war?

WORK in PROGRESS

No, not off the top of my head. I gathered my infos when I started to do some research about counterbattery procedures, after viewing WII-pictures from German Federal Archive stocks showing trucks that looked somewhat like signal trucks (similar structure), but where details appeared to be way different, which made me research the role of the "Schallmeßtrupp" (translates to sound measurement troop, but "sound detection section" would be the more proper term, I guess).

For effective fire, concealed artillery guns depended on accurately drawn matrices, and definetly on forward observers (armored vehicles or individual soldiers), who then helped to correct the fire. (Especially during the Battle of the Bulge, the German artillery units attempted to provide interdiction fire on crossroads and choke-points, to drive off or disrupt Allied reinforcements by using their matrices only, with typically bad results, with [very] few exceptions, afaik).
​

• Counterbattery fire could not be guided by such observers, unless they managed to get behind enemy lines (with proper matrix map material for long-range fire), so special sound detection devices usually offered the only means to pin-point enemy artillery, as they could enhance/amplify the bang of firing enemy artillery, even at range. Numerous sources indicate that artillery pieces can be located at distances of up to 20 km (depending on the weather situation), but this is the result of post-war detection technology employed by the German Bundeswehr. While the immediate post-war setup (after Germany's rearming process, more details can be found further down) used microphones that were placed on a line that was 10 km wide, the Wehrmacht setup was somewhat different: a set of 4-6 detection stations were positioned with offsets (means they were staggered on a line) and with a total width of 10-12 kilometers, with 2 early warning cars way in front (these were definetly used in post-war setups, it's not totally clear whether such cars were used by the Wehrmacht from the get-go), and 1 post/car serving as point of analysis. Most sources from the Federal archive (I just checked them again) indicate a max detection range of 12-15 kilometers, depending on weather conditions, where the sound detection method was way less prone to bad weather conditions than the flash detection method. Whatsoever, incoming sound levels were recorded, using a device similar to an early ECG-device, or a polygraph. Post-war devices included an oscilloscope to visualize the time difference of the different audio signals (coming from the different microphones), i am just not sure whether these were available in WWII, but the Germans had screens/tubes visualizing radar detections, so availability would be reasonable. Triangulation (by using several sound detection trucks) and comparison of detected directions, with the aid of trigonometric calculations, did then enable the Germans to pin-point the enemy artillery. It was pretty accurate. In the first World War, and between the World Wars, the Germans preferred to employ soldiers with either high-school degrees or with school-leaving certificates (after 10th grade), as they had the knowledge to perform such calculations with speed. Each truck's position, the speed of sound and current temperature and barometric pressure were vital parameters for that task.
• 
  
• The second method was the detection of light, in particular the detection of the muzzle flash. For this method, the position of targets (light sources) could be determined with angle measurement, where at least 2 special observation telescopes (prisms?) were placed at different (measured) positions. 4 - 5 motorized light/flash detection stations/cabins were used, while an additional station was responsible for the final data analysis. the system (means the several stations) was aligned on a width of 7 - 9 km, the detection depth varied (according to weather conditions) from 13 - 18 kilometers. Light detection batteries could also be used to produce panoramic images, to display the layout of the terrain for higher echelon commanders. Afaik, this method was employed on the same level as sound detection during World War I, the same goes for WW II, it's not totally clear whether that method was as successful as sound detection during WW II, though.
• 
  
• Surprisingly, the 3rd detection/observation method was the usage of observation balloons, and it's even more surprising, that the Germans employed them as late as 1942, a method well known and heavily used during WW I. Just like in WW I, a rope winch was used to lift the balloon. After that only close range recon planes were used for that task, namely Fi 156 Storch, Focke Wulf Uhu (Wehrmacht designation: FW 189 Uhu) and Henschel 126 planes. Especially the very slow Storch ("stork") was easy prey for Russian or Allied fighter planes, which resulted in a vital reduction of the German aerial recon capabilities, in addition to the very limited medium and long-range capabilities (most of the few medium and long-range recon planes were attached to the Navy to recon parts of the Atlantic (for German sub fleet commander), or were employed to conduct (rare) recon missions over Southern England.

Whatsoever, for all three tasks, measuring the area was as vital as the production of matrices (used by observers - on the ground and in the air - and by arty units). Enemy arty positions were registered on so-called "measuring table sheets", produced on the arty unit's "measuring table".

The German Army and the Dutch Army are still using the sound detection method, nowadays. An actual artillery obersation battery, as part of an artillery formation's observation batallion (which was used/renamed to combine the artillery's recon and observation units), consists of 2 early warning sections (with 2 Mercedes jeeps each), which activate 6 microphones, where each is connected to a different detection cabin (= 6 cabins on six 5t trucks). The recorded signals are then forwarded via radio to the evaluation truck, for the final analysis.

Due to the advancement of artillery observation radar techniques during the last say 25 years, sound detection became less important, though.