New TGW CRT
The following are a series of cross-posted posts from another forum where I was discussing CRT issues with a game called The Great War. To get you up to speed, I stopped my second playing of the the 1870 Redux b/c the Germans suffered two AH results on 3:1 attacks, leaving their forces gutted against 0 French losses. In the previous turn, the French had 3 1:1 attacks and only got AQ results.
Caveat: There are unfixed typos and missing words in the posts below. There are also some errors in some of the rules I was referencing as I was going from memory.
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So, I tried to build an 1870 Redux scenario to test whether the Germans could have smashed through the French frontier in 1914 instead of violating Belgian neutrality and bringing England into the war. Unfortunately, the game system I’m using has, imho, a fatal design flaw.
Caveat: this post will be fairly math-heavy.
The designer of this very detailed game system has taken great pains in capturing the flavor of World War One. There are 4 types of artillery: field, heavy, siege and heavy siege. There are 6 or so types of fortifications: fieldworks, entrenchments, forts, and three types of fortresses. Artillery can be used to augment an attack or to do pre-combat bombardments. Different types of artillery have different reduced or enhanced effectiveness against certain types of fortifications.
Plus, there’s a wealth of special units: combat engineers, siege engineers, gas engineers, heavy cavalry units, light infantry, mountain infantry, German stosstruppen, tanks, etc.
The published order of battle for this game could easily be a doctorate thesis. Not only are top-of-the-line German rifle divisions are represented (with a strength of 16 attack, 18 defense points), but even a lowly battalion of Argentinian volunteers (0 attack, 1 defense point) arrives via a neutral Italy as a German reinforcement. The rules and scenario listings take up 2 2″ binders.
It’s intense, impressive, a bit overwhelming…. and “fiddly”.
The game is based on the Europa game system, which models WWII. To capture the detail of WWI, there are two CRTs (Combat Results Tables), one for mobile combat, one for positional combat. The positional combat table is used when attacking entrenchments and other fortifications. It is very bloody for both the attacker and defender. The mobile table is used for all other combats and contains the flaw.
The mobile CRT is odds-based. To calculate the outcome of a battle, you need to divide the # of attacking points into the # of defending points to get an odds ratio; all fractions are rounded down. Frex, 17 points attacking 6 would be rolled on the 2:1 column.
The results are as follows: AE=Attacker Eliminated, AH=Attacker ½ eliminated & retreat, AR=Attacker Retreat, AQ=Attacker ¼ eliminated, EX=Exchange, HX=½ Exchange, DR=Defender Retreat, DH=Defender ½ Eliminated, DE=Defender Eliminated. When an exchange is rolled (EX or HX), the side with the fewest points is eliminated and the other side loses either a matching number of points (EX) or half the point total of the other side (HX).
To calculate which result is rolled, one six-sided die is rolled. There are only 6 possible outcomes per odds column.
Terrain and various other things can affect the result either as a die roll modifer or as a strength point modifier. Frex, attackers attacking into mountain terrain only count half their points before dividing. Attacking into woods terrain suffers a -1 modifier to the die roll.
The problem is that all this detail gets boiled away and comes down to battles determined with a six-sided die, or many rolls of a six-sided die. To illustrate fully, let me describe the first German attack in the scenario.
6 German corps attacked 3 French corps in Longwy, an iron ore resource center. The Germans were able to muster 198.5 attack points against 77 defense points, odds of 2.5:1. As the CRT only handle integral odds, this rounds down to 2:1.
However, the Incremental Odds rule allows you to roll a ten-sided die the attacker to round up. According to the Designer’s Notes, this was done b/c most historical offensives were done at 2:1 odds and the players who tested the game wouldn’t make those historical attacks b/c of the CRT results.
So, I rolled, needed a 5 or better to bump the odds to a 3:1 attack. I rolled a ‘6′ and got it.
Longwy is a resource center. According to the rules, the defender can possibly take advantage of the broken terrain that a mining center is composed of. To do so, the defender must roll a 5 or better on a d6. I rolled a 5, the defender gets a -1.
The defenders had built fieldworks in the previous turn, giving them another -1.
As the attacking force contained heavy cavalry, the attacker could try to use cavalry effects, needing to roll a 5 or better to get a +1 modifier. I rolled a 5, giving the attack a +1.
The attackers flew a tactical recon mission to the hex. I needed a 6 to get a +1. I rolled a 2.
So, the final attack was a 3:1 @ -1. I rolled a 1, modified to a 0, making the result an AH. Half the German force is eliminated and must retreat and the French may advance.
As the replacement system is quite detailed, I was able to translate this into the following:
The Germans took about 350,000 casualties in the battle, the French none. Also, the Germans retreated from the iron ore resource centers of Luxembourg City and Briey. Approx. 30 German regiments were wrecked. As the game also take national morale into account, the Germans lost over 30 morale points for the manpower loss and resource center loss and French gained close to that amount.
After trying to overcome my own loss of morale, I tried another attack. The # of points were similar. The conditions were similar, except that the French leader Foch was nearby. Again, a 5 or better needed to be rolled to get a -1 and it was rolled. The result of this battle was another 0 on the 3:1 table, an AH. Again, over 300,000 German casualties were taken vs. ZERO French.
The flaw is two-fold. First, the range of possible outcomes per odds column is too short (six) when so many die roll modifiers can come into play. Second, the results are “all-or-nothing”. Only two results, EX and HX, require both sides to take losses, and even then one side will be wiped out.
All that wonderful, gorgeous detail gets distilled to an all-or-nothing d6 roll.
So, I’ve decided to design a WWI wargame using the current system as a base and using other wargames as reference.
More to come…..
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DW uses a strength-based CRT. To resolve combats, the attacker and the defender each roll their own d6 to see how many strength points of damage are inflicted on the opponent. So, if 12 points attack 4, the attacker rolls on the 12 column to see how many points are inflicted on the defender and the defender rolls on the 4 column to see how many points are inflicted on the attacker. This way both sides receive some damage.
One side effect of the odds-based CRT is that wargamer become accountants. B/c of the integral nature of the CRT, gamers start hunting for just the right amount of points to apply to a battle so points aren’t wasted. On a strength-based CRT, each point is good enough on its own.
Frex, if the defender has 10 points of defense, the attacker wants to apply 20 or 30 or 40 points. Any other number will waste points, although other considerations may come into play, like keeping all your panzer units together, etc. On a strength-based CRT, 35 points will do incrementally more damage than 30. So, the “way of the accountant” becomes less of an issue. This is a definite plus.
One advantage with using strength-based CRTs with strength point losses is that units take incremental damage. The downside of this, however, is that each unit must carry markers like -1 or “½ strength”, in order to show its current effectiveness. In an all or nothing environment, like Europa, there are no incremental damage markers. There’s less clutter on the map, but the lack of incremental damage loses some realism.
One cool thing about the Europa system is that large units have cadres or remnants. So, when the 16-18-5 division takes damage, 18 points on defense to be exact, it flips to a cadre side of 6-8-5. This models a units staying power in that it was tough to kill and can recover some residual strength. Overall, it takes 26 points of damage to fully kill a 16-18-5 unit in Europa.
In Europa, units stay unbroken until catastrophic losses occur. In DW, units gradually lose their effectiveness over time.
Another strength of the Europa system in WWI is that almost all units have higher defensive strengths than attacking strengths, which models the inherent advantage that the machine enjoyed on the WWI battlefield when defending. In DW’s strength-based system, all units have one strength that is used for both attack and defense.
In Europa, when losses are taken, the all-or-nothing method results in units being complete unharmed or cadre’d or eliminated. In DW, and the rules enforce this, losses are spread over all units in an attack so that everyone loses effectiveness gradually.
So, before determining which type of CRT to use, I have to figure out how I want losses modelled. Both have pros and cons.
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More CRT and loss discussion before I present the hybrid solution I hit upon today.
The game I’m playing, Over There, is part of The Great War series produced by HMS. It is an extension of a WWII game system called Europa. Europa’s CRT was also odds-based with all-or-nothing ratio’d results. AH, DH, DE etc.
In any one Europa game, the # of units per hex isn’t near as large as what it is in OT. It is fairly common to have a single divisional unit in a hex defending. In the Europa system, even a fractional result, such as a DH is enough to damage/eliminate a unit. If you need to satisfy a small loss result with a big unit b/c that’s all you have in the hex, then you’re hosed. That is the reason by quarter fractional loss results aren’t in the CRT. Losing a full unit on a quarter loss result would hurt too much.
In OT, however, it is common to have large stacks of units. In that environment, quarter fractional loss results could occur and be handled reasonably. However, while common, such results would hurt small countries, like Belgium too much.
So, to recap:
I like the incremental application of force to battles to avoid the “way of the accountant”. I like incremental battle results, so that is going to be kept. Otoh, various combat research studies, such as those conducted by Trevor Dupuy, show that it was not enough to apply a quantitive force to a battle, but that having a numerical advantage had beneficial properties as well.
I prefer Europa’s method of unit losses. I like that units can be reduced to a cadre then finally eliminated, vs. the gradual strength reduction as found in Der Weltkrieg. Otoh, DW has rules in how to apply strength point losses, such that cavalry units must take losses first, artillery last, units can’t be fully eliminated until other units have been damaged, etc.
Finally, Europa’s CRT is linear, using a single d6 die roll. I think that a bell curve would be better to reduce the number of outlying results, such as the multiple AH results that occurred in the game. I think that reasonable predictable results should occur.
So, my hybrid solution will use a mixture of Europa and Der Weltkrieg concepts and methods.
First, the CRT will consist of a single column look up table. 2d6 dice will be rolled, giving a result from 2 to 12. The table will actually range from 0 to 15 to account for dice roll modifiers. The results will consist of percentage points ranging from 25 for a 0 result and 150 for a 15 result.
Battle results will consist of an attacker roll and a defender roll. Losses are calculated as the roller’s effective strength points * the percentage. So, a 16 strength attack which rolls a 0, for 25%, will apply 4 points of damage to the defender. A roll of 15, or 150%, will apply 24 points of damage to the defender.
In Der Weltkrieg, defenders counterattack at double strength (c/o of defending a fixed position), unless they retreat. Retreating also reduces the losses they receive on the attack and, under some combat results, are mandatory. Unfortunately, I don’t have the rules in front of me, so I don’t know for sure.
I will keep the defender counterattack at 2x strength points unless they retreat. The defender can always choose to retreat, but they must choose before rolling their dice.
Mandatory retreat results can be rolled if the attacker rolls high enough. The number to roll equal to or over is based on the odds level of the attack. Even with a mandatory retreat result, the defender may choose to retreat yet another hex, before rolling. A second retreat will further affect their counterattack value.
No retreat: Counterattack at 2x effective strength
1 hex: Counterattack at 1x strength
2 hexes: Counterattack at .5x strength
A voluntary retreat will reduce defender losses to 75%. So, a 24 point loss will be reduced to an 18 point loss if the defender voluntarily retreats.
Strength point loss results are applied to units in chunks. In order for a 16-18-5 unit to take a loss as a defender, at least 18 points of losses must have been received from the attacker. Losses must be applied according to certain criteria, which I won’t list now. Suffice it to say that I’m going to try to make it so that the players can’t cheat.
Frex, suppose that a 4 point loss needs to be applied against a force containing a 4 point unit and a 2 point unit. It would be illegal to apply the loss to the 2 point unit with the remainder discarded.
The pros:
- simple look-up table
- incremental application of force w/o rounding odds
- mandatory retreats tied to large-scale defender losses
- voluntary retreats for the defender
- multiple hex retreat possibility (may even have multi-hex mandatory retreats at very high odds)
- WWI mobile combat becomes bloodier than positional (trench/fortress) combat (which is very historical, though not intuitive)
The cons:
- a calculator becomes very necessary
- lots of testing to do
- not sure how to translate all the current modifiers due to map terrain and fortifications
- not sure how to apply/translate the different style of the positional CRT, which is bloodier than the mobile CRT (which is ahistorical)
To simulate the benefits of fortifications, I may have fortifications absorb some # of strength points of losses before they are applied to any defenders in the hex. I’ll have to tweak the system a bit. Luckily, if I do the historical scenario and send the Germans into Belgium, the fortress of Liege is right there.
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Ok. Here’s my new CRT. It uses a 2d6 roll which relies on a bell curve to enhance predictability. I’m not sure if that’s a good thing or not. Unpredictability is not a bad thing in a wargame. If I don’t like the results, I may switch to a d10 linear table.
| Retreat Threshold | Roll | Result |
| 0 | 20 | |
| 1 | 25 | |
| 2 | 30 | |
| 3 | 35 | |
| 10:1 | 4 | 40 |
| 9:1 | 5 | 50 |
| 8:1 | 6 | 60 |
| 7:1 / 10:1 | 7 | 70 |
| 6:1 / 9:1 | 8 | 80 |
| 5:1 / 8:1 | 9 | 90 |
| 4:1 / 7:1 | 10 | 100 |
| 3:1 / 6:1 | 11* | 105 |
| 2:1 / 5:1 | 12* | 110 |
| 13 | 115 | |
| 1:1 / 4:1 | 14 | 120 |
| 15 | 125 |
Notes:
1. The result is the percentage multiple to apply to the force’s strength. 100 = 100% or face value.
2. The Retreat Threshold is the roll on the CRT where the attacker has to roll equal to or above that number to force a defender retreat at certain odds levels. The first odds level listed in the column are for standard attacks. The seconds odds level listed in the column are for attacks against fortified positions or for a mandatory 2 hex retreat in standard attacks.
3. If the defender rolls a natural 11 or 12 (1/12 chance), the attacker cannot advance after combat, even if the defender retreats or is eliminated outright.
Example:
The German 1st and 2nd Armies attack the Belgian fortress of Liege. Liege’s defense consists of 11 strength points. The Germans attack with 6 infantry corps, 6 landwehr brigades, heavy artillery and heavy siege artillery, introducing Big Bertha, a 420mm behemoth of a cannon (see below).
Liege is an old, improved fortress. Eschewing artillery bombardment (b/c it adds nothing to the example, I’m not touching the bombardment rules), the German nominal attack strength is 154.
B/c of the fortress, infantry attackers are halved. So, 114 points of the attack are reduced to 57. The attack is also going across the Meuse River. This also halves the infantry to 28.5.
Artillery is not affected by the river, but the fortress does affect the combat effects. Heavy artillery against an old fortress is doubled. 20 points of the nominal attack were heavy artillery regiments. They now contribute 40 points. However, because it is 1914, pre-dating modern artillery tactics, heavy artillery is halved when it is supporting an attack and not bombarding. This gets the point count back down to 20.
Heavy siege artillery is quadrupled against old fortresses. 20 points of the attack are heavy siege artillery. The new strength is 80. However, heavy siege artillery gets disrupted when it moves, halving its effectiveness to 40, and, w/o modern artillery tactics, is halved again to 20.
After taking all the various combat effects into account, the German attack strength is 68.5. The odds are 6:1. The modifier is -3 due to the fortress. (I’m adjusting all modifiers by an additional -1 due to the new CRT, except for fieldworks which I’ve always felt were overrated.)
The Germans roll a 10, modified to a 7. The result is 70%, no mandatory retreat. The Belgians take 47.95 or 48 points of damage, obliterating them.
As there was no mandatory retreat, the defense fights back at 3x strength (usually 2x strength, but I’m going to experiment with 3x strength when defending in a fortress). They roll a 9. 90% of 33 is 29.7 or 30. The Germans take 30 strength points in losses. The Germans cadre two 16-18-5 divisions for 32 points of losses.
Note that if the Germans had rolled an 11, impossible with the -3 modifier, the Belgians would have suffered a mandatory retreat result. This would have reduced their counterattack to 11 points instead of 33, with a result of only 10 points in losses, resulting in only one division being cadred. However, on top of that, the Belgian heavy artillery unit is a 0 movement point unit. These units can’t retreat and are eliminated if forced to retreat. This elimination would occur before the counterattack roll, making the Belgian counterattack an 8 point counterattack. 90% of 8 is 7.2 or 7 points of losses.
With Liege vacated, the Germans advance their units in and capture the fortress. Note that if the Belgians had rolled an 11 or 12, Liege would have remained unoccupied after the battle. While the Germans would simply walk in later, the result would have given the invading forces a delay they simply can’t afford.
Had the Germans decided to bombard Liege, the results, though successful, they could have been even better. In TGW, bombardments can be used to disrupt the defenders, halving or quartering their strength prior to combat. Plus, if the bombardment is strong enough, fortresses can be reduced to mere forts. If artillery units are used to bombard, then their strengths are halved during the subsequent combat. Plus, it costs resource points to supply the bombardment in addition to any resource point expenditures to supply the combat.