Thursday, January 28, 2010

Chartless Combat

A frequent complaint about old school Dungeons & Dragons is the need for a matrix to tell you what your character needs to hit an opponent in combat. This fact is also often used as a justification for the shift to an ascending armor class system, like that introduced in D&D III, which obviates the necessity of such a chart. While it's true that old school D&D has traditionally employed a chart to present "to hit" numbers, that's not the only way the information could be presented.

In my own Dwimmermount campaign, I don't use a combat chart at all when refereeing. Instead, when a monster attacks, I roll a D20, and add the monster's Hit Dice and the target's (descending) armor class to the result of the dice roll. If the sum is 20 or more, the attack is successful. This system is simple and quick and I don't need to consult any charts.

The players write down their attack numbers on the character sheets, so they don't regularly use a chart either. Of course, they could use a similar system to what I use for monsters if they wanted. They'd just have to change the addition of Hit Dice to the addition of a class-based "combat bonus" that boiled the charts down to a single +x to hit. For example:

Fighting Man

Level

Combat Bonus

1-2

+0

3

+1

4

+2

5

+3

6

+4

7-8

+5

9

+6

10-11

+7

12+

+8


Example: A 4th-level fighting man wearing plate mail (AC 3) is facing off against an orc champion wearing chain mail and carrying a shield (AC 4). His player rolls 1D20 and scores a "2." To this the player adds his character's combat bonus (+2) and the orc's armor class (4), resulting in a total of 8. Since that doesn't equal 20 or more, the fighting man misses. The orc (who has 2 Hit Dice) attempts to attack in return. The referee rolls "15." To this he adds the orc's Hit Dice and the fighting man's armor class (3). The result is exactly 20, meaning that the orc's attack succeeds.

33 comments:

  1. is this the same as Delta's Target 20?

    ReplyDelete
  2. Philotomy uses something akin to this. We briefly talked about the benefits of having a static target number (20) for everyone involved, but I still prefer:

    d20 + bonuses/penalties + target opponent's AC >= THAC0

    ReplyDelete
  3. It's very similar to Target20, yes, although I suspect some of the specifics differ.

    ReplyDelete
  4. Looks the same as what I call Target20 -- the only difference I see is the "Fighting Man" table, whereas I just add the fighter's level (same as monster HD).

    http://www.superdan.net/oed/target20/

    ReplyDelete
  5. I’ll never understand the hate matrices get.

    Sure, it is convenient that the (A)D&D “to hit” matrices have typically been mostly regular enough to replace with a formula. And I have no beef with doing that.

    (Though—for myself—table look-ups tend to be faster than mental arithmetic, so I may very well make matrices to use when playing someone’s game based solely on formulae.)

    (While trying to recreate Dinky Dungeons from descriptions found on the web, I thought I’d replace its matrix with a formula. Then I realized that the maxing/mining out on that matrix could have a significant effect on the feel of the game. I think—if I ever get around to trying it—I’ll try it both ways.)

    A good matrix, however, can add a lot of richness with a comparatively small additional fuss. I think it’s a great tool that designers are less likely to use these days simply because of some less-than-rational animosity.

    ReplyDelete
  6. As already mentioned, this method is similar to Philotomy's, which is one that I'm going to swipe for my upcoming campaign - with tweaks.

    I'm a dyed-in-the-wool Moldway Basic fan so the method I'm going to use will reflect its 'To Hit' matrices. I'm also 'smoothing' out the attack bonuses so they're more gradual between levels than Moldvay's jumps of +2 for each level tier.

    ReplyDelete
  7. It amazes me how many different ways people can come up with to do the same math. When my campaign was still using AD&D, I had developed an ascending AC system that was basically the same math, but obviously focused on the variables in a different way. Pretty cool.

    ReplyDelete
  8. Nice!

    A big reason why I love Tunnels & Trolls is because there's no need for charts. All you need is the Monster Rating.

    ReplyDelete
  9. I used charts back in the day, of course, and later used THAC0, which I'd actually never looked into initially. Used it for years, until recently. I consider myself an old-school gamer at heart, but the ascending Armor Class system proved too good and eficient to pass up. I modified it and things have been running smoother for me.

    ReplyDelete
  10. Huh. Neat. I still don't understand the preference for descending ACs, but I suspect that it's just a generational thing that I only don't understand because I didn't grow up using them.

    ReplyDelete
  11. If you're using the old HD progression (fighters advance 1d6 every level, magic-users advance 1d6 every other level) and if you're not too worried about duplicating the old combat progression exactly, you can just add the hit dice to a PC's attack roll, same as for monsters, and it's not too far off. In fact, if you're using the old "maximum spell level is 6" rule, the maximum spell level a magic-user can use is equal to their hit dice under the old HD progression, which means you can practically eliminate the word "level".

    I've also got a slightly weird refactoring of the Target 20 algorithm in the works.

    ReplyDelete
  12. I don't have much of a head for maths, so forgive me for asking if this replicates exactly the results of the to-hit charts, or if it's more of a "close enough" thing?

    ReplyDelete
  13. Kelvin,

    It's a tough question to answer, since there's no single combat matrix used in every edition of OD&D and its clones. This replicates the results found in the charts I had been using in my campaign, but it differs slightly from those found in others, no doubt.

    ReplyDelete
  14. Kevin: The way I do it, the answer is "close enough", usually within 1 point of the values in the charts (to put it briefly: average absolute deviation 1.04).

    ReplyDelete
  15. I thought THACO resolved this sort of thing?

    ReplyDelete
  16. "I thought THACO resolved this sort of thing?"

    Why record another statistic when d20+HD+AC does the job? (Also, addition is easier for people than THACO's required subtraction.)

    ReplyDelete
  17. It's certainly easier to my mind than THAC0 ever was.

    How easy is this to translate to Labyrinth Lord? The three "core" classes are covered by Target20, but how would I model a dwarf, elf, thief, or halfling?

    ReplyDelete
  18. For a 2E fighter, THAC0 = 21 - level_fighter (*).

    For a hit,

    d20 + bonuses >= THAC0 - AC_monster (**)

    Substituting (*) in (**) and doing some algebra, we get

    d20 + bonuses + level_fighter + AC_monster >= 21 (***)

    for a hit.

    Taking into account the difference between AC in 2E AD&D and OD&D, the 21 in (***) becomes a 20.

    So James, your to-hit formula is identical to the THAC0 method for a fighter.

    ReplyDelete
  19. @Delta

    That Target20 system seems very elegant. But doesn't the linear formula d20+LVL+AC make fighting men awfully powerful awfully fast (a fighter would get +4 at 4th level, +5 at 5th, etc. vs James' more slowly progressing system where a fighter would be +0 at 1st-2nd level, +2 at 4th, etc.) Or perhaps I'm missing something here?

    ReplyDelete
  20. The problem I always had with RPG combat like this is that the player doesn't really get to make any decisions once the fighting starts.

    ReplyDelete
  21. The problem I always had with RPG combat like this is that the player doesn't really get to make any decisions once the fighting starts.

    What do you mean?

    ReplyDelete
  22. "That Target20 system seems very elegant. But doesn't the linear formula d20+LVL+AC make fighting men awfully powerful awfully fast (a fighter would get +4 at 4th level...)"

    If you played strictly by the LBB's the number at 4th level "should" be +3 (4th level hits plate & shield on roll of 15+3+2 = 20). As I say, the system is on average off by only 1 point.

    Lots of people play with a 1-point-per-level bonus for fighters. The AD&D DMG is set up that way, so I say "close enough".

    ReplyDelete
  23. @Delta
    "The AD&D DMG is set up that way"

    I just took a closer look at fighter's combat table in the 1E DMG. You're right about the average increase of +1/LVL for fighters -- though for some strange reason, in the DMG table it actually jumps up +2/two levels. I kinda like the smoother progression of Target20, with a small increase in skill every level rather than a sudden jump every other level. Though I suppose someone could make an argument for the "staggered" DMG approach.

    ReplyDelete
  24. "...though for some strange reason, in the DMG table it actually jumps up +2/two levels."

    It's really just a page-space issue. See the "Special Note" at the bottom of that page: "This table is designed to allow fighters to advance by 5% per level of experience attained, rather than 10% every 2 levels, if you believe that such will be helpful in your particular campaign."

    ReplyDelete
  25. I used the tables in the DMG when playing AD&D back in the day, but having played 3.5 for a year, I really prefer ascending AC. When I switched to Labyrinth Lord early last year, I took ascending AC with me.

    ReplyDelete
  26. "Delta said...
    'I thought THACO resolved this sort of thing?'

    Why record another statistic when d20+HD+AC does the job? (Also, addition is easier for people than THACO's required subtraction.)"

    I only mentioned THACO because James M. is clearly in favor of descending armor classes. I play a later edition of D&D myself but those editions aren't the subject of the blog.

    In the 1st ed. DMG in one of the appendices (the one with the monster stats listed) there is a column that lists a monsters: To Hit AC:0. It wasn't exactly a new concept back then.

    ReplyDelete
  27. "In the 1st ed. DMG in one of the appendices (the one with the monster stats listed) there is a column that lists a monsters: To Hit AC:0. It wasn't exactly a new concept back then."

    Of course. Nontheless, it's an extraneous concept that isn't in our OD&D books, adventures, MM listings, nor needed in the first place.

    ReplyDelete
  28. @JM

    Most RPG combat is no more granular than a skirmish wargame, except that individual players control particular figures.

    So, you can choose who/what to fight, where, and what with, but once you're in combat, you're just rolling dice with no real control, and hence no opportunity to roleplay.

    It always struck me as odd, since combat is so important to most RPGs, and central to some character classes.

    In an ideal system, there would be an element of risk management so you could roleplay your character being rash or cautions, and perhaps try to infer your opponent's morale and training etc.

    Back in the day, my own homegrown system use multiple dice for fighting: you looked at your opponent's throw and decided how many dice to hold back for your own defence.

    (However, in the end, my solution was to exchange my polyhedral dice for real swords.)

    ReplyDelete
  29. Well, zornhau, I’m running three players (who hadn’t played an RPG before) through B2 using the (Moldvay) Basic Set. They do more than just roll dice once they’re in combat. They role-play and apply basic tactics. (Not to mention special tactics that spells and thief skills enable.)

    (When I ran my regular group through B4 a few years ago, they—of course—applied tactics as well. I’ve been really impressed, however, that these new players have done a decent job of it as well.)

    I do like the ideas you mention. They’re making me think of some possible house-rules. I’m, however, not seeing how the rules prevent decisions and risk management once combat starts.

    ReplyDelete
  30. In an ideal system, there would be an element of risk management so you could roleplay your character being rash or cautions,
    I believe the new edition of WFRP does exactly this.

    and perhaps try to infer your opponent's morale and training etc.
    There's a mechanic very much like this in D&D4.

    ReplyDelete
  31. Like Robert, I've found that brand new players (sans preconceptions of how to "role-play") are often surprisingly creative about combat (and everything else), especially with a simpler system that doesn't have lots of moving parts. If there are lots of rules, I find the players tend to play to the rules rather than to the imaginative situation.

    d20+LVL+AC is an elegant little algorithm for descending AC. Is there a similar simple formula for ascending AC? I've never used ascending AC myself.

    ReplyDelete
  32. just compared this to the chart in labyrinth lord. If you just add +1 on each tier it works great. A third level dwarf gets +2, while a third level cleric and magic user would get a plus one. They can add there str modifiers and I can easily add the monsters AC to that. NICE.

    ReplyDelete

Note: Only a member of this blog may post a comment.