Question about the maths behind attack roll and defense rolls

[Bruno]

Originally Posted by SuedodeuS

If you don't like doing this, you could adopt the rules from T-bone's FEND (Fully ENabled Defenses) system, where Parry is Skill, rather than (Skill/2)+3, Dodge is Basic Move*2 (instead of Basic Move+3), defenses take a general -4 penalty, and penalties from Feints are doubled..

Quick Correction - Dodge is not based on Basic Move, but instead based on Basic Speed.

[Kromm]

The biggest reasons why we didn't use Quick Contests for combat:

1. Not all penalties to attack rolls should make the attack in question easier to defend against. In reality, the trickiest moves with the biggest penalties are often the hardest ones to defend against. On a more basic level, why would aiming for someone's foot (-4) make it more likely that the target would parry with a sword in his hand?

2. Conversely, not all bonuses to attack rolls should make the attack in question harder to defend against. Lots of big bonuses come from utterly telegraphic, predictable attacks that sacrifice speed and technique for basic aim. Some come from having a familiar weapon (Weapon Bond) or a balanced one, and mostly just help your aim as well.

3. Not all defenses use the same metric. What's Dodge based on in a Quick Contest model: DX, HT, twice Basic Speed, something else? Everybody will have an opinion. And suppose that we say it's a skill . . . now everybody needs a skill to avoid a crummy Dodge, but those who learn that skill at high levels will never need to parry.

4. You still need defenses separate from attacks, because there are some attacks that don't roll to hit (like a big rock that you have to dive out from underneath, or a scything blade trap) against which you'll need to defend. Using full skill resurrects the issue of metric . . . is it actually as easy to react (roll vs. skill to defend) as to act (roll vs. skill to hit)? Reality says "no."

5. In evenly matched duels, Quick Contests suck away drama. Neither side will do anything fancy, because he needs his full skill to contest the other guy's full skill. Thus, master swordsmen just slug each other at skill 20 instead of trying disarms, stabs for the heart, etc., which is pretty much the opposite of dramatic.

All told, the current system does the job. The only chink it its armor in 3e was solved by Deceptive Attack in 4e.

[jacobmuller]

Originally Posted by Landwalker

Why would you expect two master swordsmen to rapidly dismember each other instead of to have a long, drawn-out duel?

Possibly because he was intending to extend the Crit Success beyond 6. A Crit on your attack allows no defence, therefore, higher Crit chances for Masters would mean shorter fights than for novices. Tempting.

[Kromm]

I'm not sure whether longer or shorter fights best characterize matches between masters. "Master" has many meanings. In real life, masters tend to size each other up and then shoot in; one gets the upper hand due to a tiny difference in technical skill; and it's over in seconds. In movies, masters duel for five or six pages of script, sometimes more.

However, I'm also not sure why long is necessarily bad. Why shouldn't a life-or-death struggle use up a little more game time than other things? Flow is one thing; pacing is another. It's hard to pace a game where the most critical contests take less time than long stretches of less-critical development.

[Peter Knutsen]

Originally Posted by gjc8

The current system has the deceptive attack mechanic to make it effectively into a contest. The difference is that the attack must commit to a penalty before hand. This is a significant disadvantage.

It also gives an relative advantage to attackers who know what the defender's skill is.

Is Decetive Attack in the core books, or was it added on in a supplement? (IIRC it comes from Martial Arts, but I'm not sure.)

[Kromm]

See pp. B369-370, under Deceptive Attack. It's a core concept in the basic combat rules.

[Agent]

I believe the 3rd edition compendium offered various options. It included doing deceptive attacks functionally automatically (instead of a quick contest though maybe that was there too) where every 2 points of success over skill gave a -1 to defend. It had an option for increasing critical success with high skill as well.

Indeed I loved the 'official' sanction of the maneuver option in 4th edition. It fit right in and I wouldn't personally revert to 3rd edition experiments, though I suppose they could suit certain conceptions and game worlds.

[Mailanka]

Originally Posted by Kromm

However, I'm also not sure why long is necessarily bad. Why shouldn't a life-or-death struggle use up a little more game time than other things? Flow is one thing; pacing is another. It's hard to pace a game where the most critical contests take less time than long stretches of less-critical development.

I've had fights that took an entire session, and they were the highlight of the campaign. The problem isn't "long," it's "boring," and those two aren't necessarily the same, provided the rules of the game are sufficiently interesting. GURPS generally is.

[Kromm]

Originally Posted by Agent

I believe the 3rd edition compendium offered various options. It included doing deceptive attacks functionally automatically (instead of a quick contest though maybe that was there too) where every 2 points of success over skill gave a -1 to defend.

Yeah, that was almost good enough, but it had a few undesirable effects:

1. It was passive, meaning that masterful warriors couldn't take the initiative and ensure that they would wipe out mooks. That took some of the fun away from being a master.

2. It was random, meaning that master-on-master encounters tended to be the "Who rolls the first critical success?" contests that they were so often criticized for being.

3. It was totally risk-free. There was no chance that you'd get too fast or too tricky for your own good, which is rather common in reality.

Consciously selecting the penalty and taking the attendant risks put a lot more control in the players' hands and leads to battles that are more dominated by tactics than by luck. Overall, it's more fun and dramatic for most players.

[Anaraxes]

Our group independently invented the Deceptive Attack mechanic back in the day, and we went through similar iterations -- automatically taking the margin of success, versus pre-declaring an attack penalty, or divide by 2 versus divide by 3 (as an automatic divide by 2 is pretty powerful). We settled on pre-declared, divide by 2, as being the most fun.

I was all set to write up our nifty invention and send it to Pyramid when the new Pyramid showed up at my door, and someone had beat me to it...