DECIDE implementation notes

DECIDE has racked up many comments on this site, as well as in a related SJG forum thread.

While the idea behind DECIDE is solid, any specific implementation is a throwaway item: there are plenty of possible implementations, and you can easily drop one you don’t like and replace with another, all without tossing out the core idea. So I’m not too interested in debating implementations; any will generally fall under “yeah, whatever works for you”.

But in the spirit of designer’s notes, here are thoughts on why I use the implementation I do, with commentary on objections to it:

On melee

My implementation allows any defender a choice: commit to defense against an apparent threat without first confirming hit/miss (“immediate defense”), or commit to defense only after first confirming hit/miss (“last-second defense”). To set a difference between the two, I used a (variable) defense penalty for the latter.

There’s little (if any) objection to both the article’s idea and implementation where bullets are concerned. In melee, meanwhile, there’s general agreement that a novice fighter could realistically “waste” a defense as DECIDE allows (though no one, including me, is pushing it as something we necessarily want to worry about).

There is objection to allowing a veteran fighter to “waste” a defense, under the assertion that the vet would never do so (at least, not for game purposes).

That may be. I don’t see a problem: by employing free choice in how to defend, the implementation specifically allows the vet to never make the mistake; it never forces him to do so.

In fact, not only does the implementation leave vets free to never make the “wasted defense” mistake, it also – arguably much too generously! – allows novices to never make the mistake! True, the implementation, by making “last-second defense” more difficult, can make life hard (and short) for overconfident novices who proclaim, “I’m not going to defend unless I know I have to!” But that said, it leaves them free to try.

Good luck, little novice.

On discrete breaks

Still, there’s the claim that there shouldn’t even be an option for the vet to “waste” a defense. If that’s what you want, you can certainly change the implementation to that effect, as follows: Let defense versus bullets require action without hit/miss knowledge, for everyone, as DECIDE recommends. Let defense versus melee attacks require the same for novices, but not for vets: the latter use RAW defense, always knowing melee hit/miss before committing to defense, which they then perform at no penalty. Done.

What’s wrong with that? Nothing so far. You do have to complete it, though, before it’s ready to play. You’ve got to set the discrete “break” between novice and vet, in order to apply the rule. Do you draw the line using “highest combat skill level is X or higher”? Possibly with Combat Reflexes worked in too? Or some other definition of “veteran”?

Actually, you have to set breaks in two dimensions: the break between novice and vet, and the break between melee attacks and bullets. No, the latter isn’t obvious: there’s an infinite range of speeds in between. Somewhere along that speed continuum is a break where the vet goes from 100% RAW ability to know hit/miss in advance, to no ability to do so. Does the break occur when the missile is as fast as an arrow? A crossbow bolt? Where? Does range of the missile, as some have suggested, further come into the picture? Or is it just a matter of whether or not you can visually track the missile (GM call)?

The breaks don’t need to be anything tricky; I’m not setting out to make them look difficult. I only note that they need to be set.

One thing I like about my implementation is no need to set discrete breaks. Both dimensions are already covered, if somewhat abstractly, by penalties. The penalty that the vet can easily afford is one that the novice can’t; thus, in practical play, judging that hair-splitting miss becomes a feat for the vet only. Likewise, the variable penalties mean that even the vet will find it prudent to seek cover as missiles become faster, rather than retain full hit/miss predictive ability regardless of missile speed (until that break point where, poof, he loses the ability completely).

That nicety doesn’t kick other possible implementations into the dust, but I do like the simplicity of not having to set breaks. Yet it’s only a mechanical nicety. There’s still a realism objection to tacking any penalty onto the vet for “last-second defense”. Is the penalty unrealistic?

On the defense penalty

To correct one apparent misconception, my implementation’s “immediate defense” doesn’t have a vet (or novice, for that matter) make a defense before it’s clear that a legitimate threat exists. It injects no funny business of making defenses way too early to be effective (though with or without DECIDE, you could certainly interpret a really bad defense roll as precisely that, if you like).

Ideally, a defender commits to defend (or not defend) after he’s certain that the blow will hit (or miss). My implementation simply adds the option to commit at the split-second prior to that, where the blow could be on target, but the defender hasn’t confirmed whether it will be.

If there’s anything creating confusion there, it’s probably poor naming on my part. My names “immediate defense” and “last-second defense” are perhaps still very poor. I’m only looking to name these concepts: “Standard defense versus a seemingly legitimate threat”, versus “The same, but taking an extra split-second to make 100% certain that the attack’s not going to fall short by a hair”. If you’ve got better labels, let me know!

Names aside, here’s a simple example of a vet taking the penalty in question, which feels plenty realistic to me:

An Orc swings his sword at our hero, Sir Vet, making one normal Attack maneuver per turn – a standard, one-on-one combat situation.

Sir Vet has no reason to hold back his defenses and “confirm” hit/miss. There’s no need for him to say “I’m not going to take action unless I know that’ll hit!” Against any Orc blow that looks to be a reasonable threat (i.e., is not a crit miss or other lousy TH roll), he’s free to say “I defend!” and actively use, not “reserve”, his parry. That single parry is “free” in GURPS, creating no penalty elsewhere; Sir Vet has no reason to hold back the parry. So he intentionally meets the Orc’s attack nice and early, earning a +1 bonus for immediate defense. 

But now another Orc joins the fight, and Sir Vet is the target of two Attack maneuvers each turn. He’s no longer free to parry every blow; if he parries the first blow in a turn, he’ll take a hefty -4 to parry the second. If at all possible, he’ll want to reserve his parry when that first blow comes, using the defense only if it’s absolutely necessary; after all, a second attack is also on its way. When the first blow comes, Sir Vet holds back for a tiny instant, committing to a parry only when he’s certain that the blow won’t miss by a hair. He’s fighting differently from how he was a moment ago.

My implementation makes this cautious, selective style of defense a (slightly) more difficult task than less-harried, freer defense, and I find that works fine for novices and vets alike. Defending with intent to “reserve” defenses whenever possible is harder than defending with no such restrictions.

That’s the key behind defense penalties: the “last-second defense” (or whatever it should be called) is a more difficult task. The way to handle more difficult tasks in GURPS is via an appropriate mod, which is applied equally to both high skill and low. Letting high skill have its usual effect (in this case, a better defense score), while also removing a certain penalty because skill is high, is “double-dipping” and generally isn’t done in the game.

In summary, I like the penalty-based implementation for its non-discrete application of effects in both the novice-vs-veteran dimension and the slow-vs-fast-attack dimension, more than I would like arbitrary, binary break points. I also like it for its ease of play, for its lack of any patches, extra steps, extra rolls, special cases, and other futziness, for its use of a simple, standard penalty mechanism for task difficulty, and, yes, for its realism.

If anyone still disagrees on the realism issue, then let’s happily disagree!

But a penalty??

There have been objections to the implementation (and even the DECIDE idea) for making defenses “harder”. What can I say? Yes, removing unnatural predictive powers from defenders does make their job harder. I call that an improvement, and will note that it applies equally to everyone; there’s no special picking on PCs.

Fortunately, for the main application of DECIDE – knowledge of bullet hit/miss – most every commenter agrees that the change is indeed an improvement. For those who don’t like its application in melee, the solution is easy: don’t use it.

But what if you do happen to like my DECIDE implementation in melee, but just don’t like any penalty involved (even a small one applied to PC and foe alike)?

You’re in luck: there’s a dead-simple adjustment you can make. Just add +1 to all the suggested modifiers. The result in melee:

You make a normal melee defense at +0 (instead of the -1 I initially used in the first draft) when you confirm TH before committing to defense. This is exactly per GURPS RAW in all effects.

Or, you can defend at +1 (instead of the +0 I initially used) if you commit to a defense before confirming TH.

Hmm. Although I’ve always been happy to play my “old” implementation, I rather like this little change! There’s just that +1 difference from the old, but it’s perhaps much better design. It leaves everything unchanged for a RAW melee defense, in which you first confirm hit/miss. Meanwhile, the +1 to defense for not first confirming hit/miss emphasizes that this is a new defense option: a defense that quickly commits to countering any legitimate-appearing threat, but which carries the risk of “wasting” the defense against an attack that would have missed by a bit.

In other words: There’s no change for those choosing the RAW defense option, and a change only for those selecting an interesting new option. That’s a design approach I try to use through all my hacking, but had neglected to apply to DECIDE. Maybe I should have been playing it this way from the start!


Would that simple “+1” tweak make for a better implementation than the current one? Let me know, readers. (Edit: I went and made that change to DECIDE. It’s “official” now.)

And whether you think that change is better or not, if you’ve got some totally different, shinier, preferred way to handle the whole fershluggin’ deal, then that’s the implementation for you. Happy defending!


  • bignose

    Tbone here: Doh! Bignose wrote a reply to say “I think DEFEND is a good idea, and an improvement, melee penalty and all. It would also work well with FEND.” (My paraphrasing.)

    Stupidly, I hit “edit” instead of “reply”, and accidentally wrote over his comment. (Umm, better remove that ability from my account…) Sorry, bignose! I need to pay attention.

    The best I can do here is give my reply to what I erased:

    Yeah, things could work interestingly with FEND. Since that house rule cranks defense scores way up to start with, it then has to look for ways to bring them back down: increased penalties of various type, no PD (now part of 4e anyway), and a general penalty. Adding in a penalty for the “wait and confirm TH” defense would fit right in.
    Still, as most people won’t use FEND, and as I do like the game design goal of “no change unless an option is chosen” (which I normally try to follow, but forgot to do so here : ), I am leaning toward modifying the article to use the +1/+0 mods for melee.
    Thanks for the comments!

    • Rob Conley

      I think the psychology of getting a group of players is better with the +1 than the original proposal. It feels like you are giving the players more options than taking something away.

      I still disagree with the premise that waiting for a melee attack is committed before defending is somehow more difficult. It is certainly something that comes through experience and training. But also there is the fact there is the problem that if you defend too soon the attacker can adjust and make the hit.

      I think for the purpose of simulation that a lot of this goes down further than what a RPG is capable of and still remain fun and playable.

      I don’t have Martial Arts in front of me but it has a simple definition for untrained combatants vs trained combatant.

      • tbone

        Yes, I think the psychology is better for the +0/+1. It’s always good to have a choice between some new option, and no change at all from what players are used to. I’ll probably rewrite later, to that effect.

    • bignose

      I don’t know what this “DEFEND” is of which you speak. But I think DECIDE is a good idea, and an improvement, melee penalty and all. It would also work well with FEND.


      • tbone

        Uh, yeah, DECIDE. Now that I think about it, I recall that being the right name. : )

        Simple explanation: I was rushing to reply to comments while tossing things into a suitcase for a little sunny vacation time. I inadvertedly discovered the ability to edit others’ comments with a misplaced click, and while trying to quickly clean that up, got my own article’s name wrong!

        I should be back to normal now, for what that’s worth. And with a tan, to boot. Like a nerdy George Hamilton.

  • Esteemed Visitor

    As a way to implement defense rolling before knowing ‘hits’, you might simply consider requiring that any PC using All-Out Defense, Retreat (including drop), feverish defense, and Defensive Attack MUST declare defense rolls before knowing whether an attack hits.

    In this way, any PC choice bonus to defense (not DB from Shields and the like) can only be utilized if you commit to the defense earlier. The “penalty” for not deciding earlier is the lack of improved defensive options.

    I myself think that it is probably unnecessary, and would just use the standard DECIDE idea, as it is simple and elegant (and I don’t much care for the +1 concept).

    To me, a fighter who is skilled enough to gauge whether an opponent will probably hit is probably using an Evaluate maneuver to observe him closely, and will get another type of benefit from his observation (he may ‘waste’ a defense on a miss), but he’ll get a +1 to hit next turn.

    • tbone

      Hmm, interesting! The actions you list certainly go well with the DECIDE commitment to defend (i.e., “I defend!”, as opposed to RAW’s “I defend only if I absolutely must”).

      Overall, I continue to prefer the basic DECIDE method (and it seems you do too): “I defend only if I absolutely must” is simply tougher to perform than “I defend!”, and like anywhere in the game, a penalty handles tougher actions just fine. And it still meshes with what you describe: a fighter who’s chosen AOD or Defensive Attack won’t have to choose “I defend!”, but given his desire for defense, it’s hard to imagine why he wouldn’t. Likewise, I can picture a fighter who’s willing to Retreat, but only if he’s sure it’s necessary; that fighter remains free to choose “I defend only if I absolutely must” and yet Retreat if needed. All nice and simple, with no restrictions on mixing and matching choices.

      That said, I know there are those who are warm to the general DECIDE idea but not the suggested penalty, and prefer to restrict a fighter from such-and-such actions or combinations of actions, based on skill level or other factors. Those folks might find your suggestion perfect. It’s easy to work with: if you want improved defense options, you need to commit to defending. Nice and neat.

      Using DECIDE, there’s any number of ways to set who can and who can’t know TH in advance, and under what conditions… Thanks for suggesting one more clear way to handle it!

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