1D10 versus 2D10

[Ur_Vile_WEdge]

Most tournaments these days use 2D10, as I understand it.

Also, at least to me, 2D10 has the pro that it encourages players to mass their armor. In 1d10, you'll want just enough arm/mech involved to be able to call a blitz if you want, and more are generally wasted.

2D10 rewards the historically accurate "We commit all of our tanks to where we want the breakthrough."

[paulderynck]

My experience has been more people use 2D10. However, the game's designer still refers to 2D10 as an optional rule that replaces the "standard" CRT.

[WIF_Killzone]

What happened to the trust 2 x 6 dice. Worked for me many moons ago, what was the logic behind the change and then the change again?

[juntoalmar]

Hi,

I have started a game with 2D10 for first time. I kind of understand it, but I haven't found in the rules or in the forum the conversion from 2:1, 3:1, 4:1 to +5, +6, +11...

This is kind of embarrassing... as it seems to me that the answer has to be very obvious, but I just don't find it!

[Orm]

ORIGINAL: juntoalmar

Hi,

I have started a game with 2D10 for first time. I kind of understand it, but I haven't found in the rules or in the forum the conversion from 2:1, 3:1, 4:1 to +5, +6, +11...

This is kind of embarrassing... as it seems to me that the answer has to be very obvious, but I just don't find it!

At the end of RAC you find the 2D10 table.

[Orm]

And here is the 2D10 odds table.

[juntoalmar]

Ok! Thanks a lot!

I found it in the RAC. The fact is that the table is in page 174 of RAC next to Weather Effects, and in my quick scan I thought the table was related to weather.

Thanks again!

[paulderynck]

Figure out the odds. Double them. Are you playing fractional odds? If no, then round off and you have the number to add to the dice total. If yes, then use the remainder to determine whether you can add one more.

Simple example: 25 to 4. That's 6.25 to 1. Doubled, that's +12.5. Fractional odds? If no, then roll two dice and add 12 and look at the table to see the result. If yes, then roll one more die. The fraction is point 5, so if your roll 1 to 5, add one more to make it +13, but if you roll 6 to 10, then it remains a +12.

On top of the odds are all the modifiers for armor, engineers, cities, HQ support etc. Those are added/subtracted to the base die roll modifier (+12 in the example above) before the fractional +1 (or not) is determined.

[warspite1]

Wish I'd found this thread before setting up....

Early days but I think 2D10 is going to take a lot of getting used to....

It may just be a case of unfamiliarity with something new but equally, at present I just don't like the 'feel' of 2D10.

[Ian R]

ORIGINAL: warspite1

Wish I'd found this thread before setting up....

Early days but I think 2D10 is going to take a lot of getting used to....

It may just be a case of unfamiliarity with something new but equally, at present I just don't like the 'feel' of 2D10.

It's easy. organize 7-1 attacks, which, if everything else nets out gives you a +14DRM. And a 10% chance of a poor result, but one that still affects the defender. You can't get 7-1 everywhere, so you start adding tanks, engineers, etc to get the modifiers up high.

For what it is worth, playing solitaire I am using the 1D10. I am not using the blitz bonus rule. Also, whilst I am using divisions in a minimal fashion, I am not using artillery, engineers, or mass breakdowns optionals - in fact I do do not use breakdowns at all, the MPs get the divisions they build and that is that.

I find this bloody enough, and variable enough, for enjoyable solo play. YMMV.

[Centuur]

The feel of 2D10 is totally different from the 1D10.

The trick with 2D10 is to watch the modifiers you can get (both positive and negative). They are directly calculated above the result you get from the odds ratio.

Those modifiers are everything for both the defender and the attacker. Any attack with a final result of +11 after all modifiers or more is a good one, IMHO. Any attack lower than +9 I consider to be very risky.

Personally I prefer 2D10 because of the higher chance of losses, because of all the extra units in play.

[brian brian]

To understand the 2d10 table, it helps to step back and re-examine the 1d10 chart and how die modifiers work on it.

And never forget that 1:1 = +2, 2:1 = +4.

Let's say you have a desperate situation and you need to make a 2:1 attack you would rather not make, but success would save the theater in question. Always helpful to attack a flipped unit, yes? So you try a Ground Strike on the defenders first, and you flip one of their corps/army units. Now you get a +1 on the 1d10 attack. If you read the 1d10 table results for 2:1 from 2 through 11, you will see that they are basically the same as the results for a 3:1 dice range of 1 through 10. (there are a couple minor discrepancies in column comparisons)

Now on the 2d10 table, attacking a flipped unit at 2:1 is a +6 attack, because you get a +2 modifier for the flipped unit - basically the same thing as an odds column shift.

The same dynamic is at play for "Blitz Bonus", which is not even optional on 2d10, iirc. On 2d10, an ARM or MECH defending in clear gets an automatic -2 in the 2d10 calculation - the same as reducing the odds by one column on 1d10, where it would instead receive a -1 to the land combat die roll, not a column shift.

That dynamic of some things being a column shift (weather) and some things (flipped, blitz mod for attacker or defender) being a die modifier in the 1d10 system is eliminated in 2d10 - everything is a die modifier.


The other big difference in 2d10 is that there are far more "half odds level" modifiers - things that aren't included in the 1d10 system at all. So attacking a city hex starts out with an automatic -1 in 2d10. An armored division can get a 1 point die modifier in 2d10 but is ignored in 1d10, etc.

And thus there is more room in the operational decisions on the map to reward combined-arms approaches. Engineers hold value. Not just armor divisions, but anti-tank assets hold dice influencing value.


Now the dice mechanism is different too in that the most likely die result is 11. You can still roll well, or roll poorly with 2d10; anything 2-4 is going to be little different than rolling a "1" in 1d10. But as you make more attacks in a single impulse, there is less chance that you will roll a "1" three times in a row, or even roll less than 5 sequentially. Any given attack has the same likely general outcome in either system, but a series of attacks is more variable in 1d10.


Also with air units, keep in mind how adding factors to a combat works, vs. attempting to get die modifiers. Generally it is not worth trying to Ground Strike a single unit though there can be other reasons to try it, like an out-of-supply defender. If that unit has 5 defense factors and you have a 5 factor Stuka, using the 5 factor Stuka as Ground Support automatically raises the odds level by 1 - the same as getting a +2 on the 2d10 calculation. Whereas a Ground Strike mission only has a 50% chance of success doing that, and costs you an air mission which is not unlimited, while flying Ground Support is unlimited.

But against a stack of 2 units each with 5 factors, using that same Stuka as Ground Support only gains you an automatic +1 on the 2d10 as 5:10 is half of the odds level. Sending the Stuka in as a Ground Strike can have 3 outcomes: neither unit flips (25%), one unit flips and adds +2 to the attack (50%), or both unit flip and adds +4 to the attack (25%).

And for anyone with only electronic experience playing World in Flames "flip" = "dis-organize" in MWiF.

[brian brian]

p.s. I don't think learning 2d10 will have much impact in Poland when Germany is only attacking Poland. All attacks will be overwhelming high odds affairs anyway. You will start to see the dynamic of when to use an HQ in an attack to help reduce the penalty for attacking a city. That risks flipping the HQ and removing your capacity to re-organize the attacking units and trying again, but also makes the initial attack more likely to succeed.

Early operations in China are not much different either; Japan's ability to flip units is not like Germany's and there are rarely any units with tanks on the map. But in China, 2d10 HQ Support becomes a key decision for Japan in their land combats. HQ Support is an automatic die modifier in 2d10, not an additional die roll.

For Germany, the nuances of the 2d10 modifiers do start to become very important as they attempt to break through in Flanders, and the same is true for the French trying to stop them.

[paulderynck]

I've always felt 1D10 with Divs and Arty but without the Blitz Bonus is pretty much WWI.

[Elessar2]

ORIGINAL: Neilster

I haven't played with 2D10 but as it gives a distribution with more average results, I'd be inclined to prefer it. Weird results are possible but rare.

Actually, a 3D10 table would be good. It's gives a reasonable approximation of the Normal distribution without ridiculous complexity.

Cheers, Neilster

Or you could use 3D8, subtract 3 from the roll, a zero becomes a one, a 21 a 20. [or count 8's as zero's]

[rkr1958]

My feel for the 2D10 table comes from my 2D10 Excel-based calculator. It's with this calculator that I can examine the odds between an assault and a blitz.

[rkr1958]

Or more significantly how much would +2 in HQ support, for example, increase my PWIN (i.e., probability of win).

[rkr1958]

I've attached ver6 of my Excel 2D10 calculator for any and all who wish to use it.

The cells are locked so that the player can only input into certain cells. Also, the range of values in those cells are checked so that the user can only enter "valid" values.

The player inputs include:

# Attackers = total number of attacking ground units.

# Defenders = total number of defending ground units (does NOT include notionals). If only notionals are defending then the user would enter 0.

# Invaders = number of attackers that are invading (i.e., air drop or amphibious). The number of invaders is a subset of the total number of attackers. For example, if a hex is being amphibiously invaded by 3 land units and also attacked overland by 4 land units then the total number of attackers is 7 and the number of invaders is 3.

Extra Loss = is a flag as to whether or not the attacker is eligible for an extra loss (=1) or not (=0).

Odds = are the odds.

PWIN = probability that one or more of the attackers will survive and be eligible to advance into the defended hex.

Def Shat/Surv = chance that one or more defending units survive and are shattered.

Ex Def Kill = expected number of defending units killed.

Att 3 Loss = chance that the attacker will have to lose 3, or more, of their attacking units.

Att No Loss = chance that the attacker loses no units.

Att Ex Lost = expected number of attacking units lost.

Att Org = chance that all attackers remaining organized (except for an HQ that provides HQ support).

Att 1/2 Org = chance that half (round up) of all surviving attacking ground units remain organized.

Att Disorg = chance that all surviving attacking units are disorganized.

Ex Att Disorg = expected number of attacking units that will be disorganized.

For Blitz.

Brkthrough = flag (0 or 1) if a breakthrough is possible.

Breakthrough = chance of achieving a breakthrough (of course if Brkthrough=0, then that chance will always be 0%).

[Shannon V. OKeets]

Die roll probabilities summing two 10 sided dice, are simply 1 (up) -> 10 (down) -> 1. The air-to-air combat results table shows this on the right hand side.

For the 2D10 CRT I perform the following calculations - which can be done in your head.

1 - total the attacking factors, total the defending factors.

2 - double the attacking factors and divide by the defending factors.
To do this more easily, take multiples of the defending factors until you find the one just less that the attacking factors doubled. For example, I have 48 attacking factors against 13 defending factors. Multiples of 13 are: 13, 26, 39, 52 (# of cards in a deck of cards), 65, 78, 91, 104. Double 48 is 96, so the DRM is +7, with 5/13 left over. If I can add 4 factors of air support, that will give me 52 attack factors, doubled to 104, and I will have a DRM of +8.

3 - Memorize some crucial numbers on the 2D10.
- A +12 means the lowest die roll is 14 which kills a single defender using the Assault table. In the above example, I only have a +8 (with air support). That means I am 4 DRM short of certain death for a single defender in the hex. The odds of rolling too low to kill a single defender is therefore: 1+2+3+4 = 10%.

- There are 5 die rolls on the 2D10 Assault table with the result of 1 defender dies. Starting with +17, 2 defenders will certainly die. I am 9 DRM short of achieving that (17 - 8). The risk of not killing two units is: 1+2+3+4+5+6+7+8+9 = 45%. I have a 55% chance of killing 2 units.

- To kill a 3rd unit (and with 13 defending factors, there most likely are 3 defenders in the hex), I need the DRM + die roll to be 20 or higher. I am 10 short of that, which is 55% likely to fail. 45% chance of killing all 3 defenders.

Memorize: +12 => kills 1; +17 kills 2, and +18 kills 3.

For the Blitz table, there are similar cut off points, but usually you are trying to make sure the attackers don't take any losses.

[Ian R]

ORIGINAL: Shannon V. OKeets

- To kill a 3rd unit (and with 13 defending factors, there most likely are 3 defenders in the hex), I need the DRM + die roll to be 20 or higher. I am 10 short of that, which is 55% likely to fail. 45% chance of killing all 3 defenders.

Memorize: +12 => kills 1; +17 kills 2, and +18 kills 3.

This is why I said a DRM of 14 gives you a 10% chance of a poor result - probability of rolling adjusted 16, 17, 18, 19 are 1+2+3+4 = 10%. Putting that another way, you are 90% chance of an S or B result.