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-   -   The game mechanics for a stealth sneak-up and backstab?.. (http://forums.sjgames.com/showthread.php?t=24663)

vicky_molokh 02-27-2007 07:03 AM

The game mechanics for a stealth sneak-up and backstab?..
 
Greetings, all!

Basic mentions needing to make Stealth rolls for sneaking up on someone for a garrote attack. Kromm mentions stealthy evaluate maneuvers...

Is there some set of guidelines as to the modifiers, frequency of rolls etc. when using Stealth? To me, the skill seems like it needs a long description (probably equal to half of Combat Lite), but it doesn't.

Thanks in advance to all who answer!

sir_pudding 02-27-2007 07:09 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Quote:

Originally Posted by Molokh
Greetings, all!

Basic mentions needing to make Stealth rolls for sneaking up on someone for a garrote attack. Kromm mentions stealthy evaluate maneuvers...

Is there some set of guidelines as to the modifiers, frequency of rolls etc. when using Stealth? To me, the skill seems like it needs a long description (probably equal to half of Combat Lite), but it doesn't.

Thanks in advance to all who answer!

You need to make Stealth vs. Hearing rolls each turn to sneak up on someone (starting when they have a chance to actually hear you at all, ie. for an average person when the total penalties to Hearing are >=-7). You may evaluate (or take any maneuver really that allows movement) as you approach. When you attack (assuming that you won the contest each round), the target is unaware and therefore gets no active defense. This should also count as either Partial or Total Suprise, on the next turn.

NineDaysDead 02-27-2007 07:10 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Quote:

Originally Posted by Molokh
Greetings, all!

Basic mentions needing to make Stealth rolls for sneaking up on someone for a garrote attack. Kromm mentions stealthy evaluate maneuvers...

Is there some set of guidelines as to the modifiers, frequency of rolls etc. when using Stealth? To me, the skill seems like it needs a long description (probably equal to half of Combat Lite), but it doesn't.

Thanks in advance to all who answer!

What Kromm had to say in 3rd Ed:
Quote:

Also, remember what "backstabbing" originally meant in AD&D: a surprise attack from behind on a one-minute timescale. In GURPS, the best way to represent this is to let a character who has won a Quick Contest of Stealth (or possibly Camouflage or Shadowing) vs. his victim's Sense roll by a lot -- say, by 10 or more -- to attack by "Total Surprise" (see p.B122). He will then have 1d seconds during which the target cannot react *at all.* He will be able to attack several times, unopposed; the GM might even give him the +4 to hit from the "Instant Death" sidebar on p.B126, in which case he will be able to target vital areas with ease.
Since the victim is not fighting back, the assassin might as well do an All-Out Attack, giving a further +4 to offset hit location penalties to attack vital areas, or +2 damage to get through armor, or simply more attacks. Someone who can strike the eyes (-9) or eyeslits (-10) at +8 (+4
for unsuspecting, immobile target, +4 for All-Out Attack) is going to cause serious hurt. So is someone who is striking at +2 damage. And 1d seconds' worth of attacks -- i.e., 1d attacks, or 1dx2 attacks if you choose to go All-Out for bonus attacks -- is almost certainly good enough to do the job.

However . . .

Do NOT allow this in raging combat. This is a surprise assassination. None of the above is valid if the target is in a fight and expecting an attack. Yes, you might get behind him, but you will not get 1d free shots at him, you will not get +4 to hit for an unsuspecting target, and if you risk an All-Out Attack and fail to take him down, he can just wheel and cut you down while you are standing there defenseless. The move above *might* be a legal opener to a battle, where the thief type sneaks in, takes out a tough foe, and then all hell breaks loose as the thief's allies and foe's allies draw and have at each other.

Do NOT bypass DR. DR doesn't magically go away because you have surprise, and while it is all cinematic and cool for armor to have these "chinks" and "seams" people keep talking about, most armor has overlapping
protection to avoid this, and most weapons simply are not slim enough to take advantage of such openings in any event. There is a reason why special daggers were made for the purpose. Of course, Thieves' Guilds
might do very brisk business in misericordes with narrow, tapering blades. . . but then carrying one will mark you a killer (no, you can't just hide it -- it has to be *long* to be effective at piercing armor).

Remember that this is NOT effective against foes with Combat Reflexes. Citizen Fred, Joe the Town Guard, Oggh the Ordinary Orc, etc. will probably be fair game. Don't expect a ninja or ranger, or a predatory cat, or some grizzled veteran carrying 47 separate weapons to fall for it. You might still get an attack from behind, but the target will not freeze up -- he will just turn and pummel you if you fail to take him down.

SP.
Another thread on the matter.

vicky_molokh 03-07-2007 12:48 PM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Quote:

Originally Posted by sir_pudding
You need to make Stealth vs. Hearing rolls each turn to sneak up on someone (starting when they have a chance to actually hear you at all, ie. for an average person when the total penalties to Hearing are >=-7). You may evaluate (or take any maneuver really that allows movement) as you approach. When you attack (assuming that you won the contest each round), the target is unaware and therefore gets no active defense. This should also count as either Partial or Total Suprise, on the next turn.

Do I roll each turn even if I follow a target for many seconds, perhaps minutes?

Also, the hearing penalty is hard to find. What is the 'default range' for sound-based Stealth?

Turhan's Bey Company 03-07-2007 12:57 PM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Quote:

Originally Posted by Molokh
Do I roll each turn even if I follow a target for many seconds, perhaps minutes?

Also, the hearing penalty is hard to find. What is the 'default range' for sound-based Stealth?

P. 358 has some relevant stuff, though not much. There's no "default" range for hearing, but I'd put the "hearing range" for an ordinary footstep at the bottom of the scale and consider starting to roll when total hearing penalties for distance, walls and other sound-absorbing stuff in the way (having a wall in the way is probably good for a very large penalty), and background noise fell below -10.

noctrine 04-04-2009 01:46 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Sorry for the thread necromancy, but I was wondering if there has been any word from Kromm about the 4e mechanics of stealth. As far as I can tell, Molokh's questions in this thread haven't been answered elsewhere in the forum, and I don't find the word "stealth" in the list of official FAQ topics.

Thanks in advance!

Ulzgoroth 04-04-2009 01:56 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
The noise and distance material in High-Tech (discussing silencers, but generalizable) probably has bearing.

The backstab itself is well covered by Telegraphic (optionally All-Out) Attack for whatever target location seems best.

How much rolling for stealth the sneaking-up process requires, I don't know.

Crakkerjakk 04-04-2009 01:56 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Personally I'm against "roll every turn" on an all-or-nothing thing like stealth. The nature of probability means that your chances of failing are snowballing every time you roll again. And a single failure I would assume means he notices you. So my ideal solution would involve a small amount of rolls in order to execute this. It shouldn't be easy as it's pretty close to an insta-kill if you're standing behind someone with a weapon and they don't know it, but it also shouldn't require a whole bunch of rolls, IMO.

EDIT: Normally I make one stealth roll per character for every "scene" in which they're trying to sneak. I think counting stalking a target to backstab could be considered such a scene. They make their stealth roll, the target makes their perception roll. If the ninja makes it by enough that they can get all the way behind them before the target successfully hears them, they get their backstab. If the target only makes it by enough to hear them within x amount of yards, I let the player sneak up till they get that close then the target hears them and regular action commences.

Lupo 04-04-2009 07:57 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Quote:

Originally Posted by Molokh
Do I roll each turn even if I follow a target for many seconds, perhaps minutes?

Also, the hearing penalty is hard to find. What is the 'default range' for sound-based Stealth?

There is no "hard rule" for this AFAIK.
(There is an abstract rule in Dungeon Fantasy).

Usually I require a Quick Contest between Stealth and Perception. This will allow you to get at, say, 10 yards from your enemy.
Then I ask the PC for more rolls if he wants to get closer... a good guideline could be the Range/Speed increments, e.g. one roll at 10 yds, then another at 7 yds, then 5, 3, 2 (and then, ATTACK!)

weby 04-04-2009 08:12 AM

Re: The game mechanics for a stealth sneak-up and backstab?..
 
Well, basically with telegraphic attack available you do not need evaluate when approaching from behind..

As for how often to roll.. Well the rules do not say anything specific except the hunting thing..

"A successful roll (and about 30minutes) gets you within 30 yards of most animals. Another roll, at -5, gets you within 15 yards."

But there is apparently no opposed roll..


As for how I have done it is: 1 day at distant stationary observation like a OP. 1 hour of following someone at edge of vision range behind. 10 minutes of closing at far distances(actual distance varies with the terrain) 1 minute at medium distances. 10 seconds at close distances(about the last 10 meters normally, requiring 1 roll for s stationary target, 2 for slowly walking sentry) and 1 second if they stay really close to the target..


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