Opposed Rolls in Classic Traveller

[Supplement Four]

I'm writing this post with Employee 2-4601 in mind.

I was reading a White Dwarf Traveller article by Andy Slack, and something he wrote made me think of opposed rolls.

Typically, we think of opposed rolls in the MegaTraveller sense of the term. We think, "One side rolls, then the other side rolls, and the highest roll wins."

Andy had a good idea. A simple idea. And idea that's really already used in Classic Trav (for instance, with parry DM on Brawling Combat).

Here's my take on handling Opposed Rolls in Classic Traveller. It's a little of what's said in Book 1, mixed with a little of what Mr. Slack said in his article, with a little of my own S4 two cents thrown in...

================================================

Say you're in a situation where an Opposed Roll is called for. Off the top of my head, let's say Alani is tyring to download the database from a computer, but Alani has been dectected by security. Security is attempting to shut Alani out of the database as soon as possible.

First, we're only going to have one roll in our Opposed Roll. Not two, like you'd normally expect (Alani rolls, then Security rolls.)

The party attempting to accomplish something is the party that makes the roll.

The GM picks a number, 2-12, for Alani to roll. The GM can gauge the base difficulty this way. (If he wants, he can use the UGM modifiers, modifying the roll starting at 8+, up or down, based on how hard or easy the GM thinks the roll should be.).

Alani is allowed his Computer skill as a DM. Security is allowed their Computer skill as a penalty DM. The GM may assign other DMs as he sees fit.

That's it. The "opposed" part comes with the adding and subtracting of the two Computer skills.

Maybe the GM thinks it's pretty easy to for Alani to download the data normally. Use the UGM as a guide (Difficulty of 8+, -4 for EASY), the GM states that the roll needed is 4+. Alani can use her Computer-2 skill as a DM.

On the other side of the network, Security is furiously working the panel to shut Alani out. That Security Officer's Computer-3 skill will be used as a penlaty on Alani's throw.

So...

Alani ends up throwing this Opposed Throw:

2D +2 -3 for 4+.

2D -1 for 4+.

---------------

Or, if you want to keep the UGM 8+ total on all of your throws, you can express this same roll as:

2D +2 -3 +4 for 8+

2D +3 for 8+.


That's kind of a long winded post to explain a simple idea.

What I like about it is that you're only throwing one throw...throw it, and keep on playing.

-S4

 

[Supplement Four]

I'm writing this post with Employee 2-4601 in mind.

I was reading a White Dwarf Traveller article by Andy Slack, and something he wrote made me think of opposed rolls.

Typically, we think of opposed rolls in the MegaTraveller sense of the term. We think, "One side rolls, then the other side rolls, and the highest roll wins."

Andy had a good idea. A simple idea. And idea that's really already used in Classic Trav (for instance, with parry DM on Brawling Combat).

Here's my take on handling Opposed Rolls in Classic Traveller. It's a little of what's said in Book 1, mixed with a little of what Mr. Slack said in his article, with a little of my own S4 two cents thrown in...

================================================

Say you're in a situation where an Opposed Roll is called for. Off the top of my head, let's say Alani is tyring to download the database from a computer, but Alani has been dectected by security. Security is attempting to shut Alani out of the database as soon as possible.

First, we're only going to have one roll in our Opposed Roll. Not two, like you'd normally expect (Alani rolls, then Security rolls.)

The party attempting to accomplish something is the party that makes the roll.

The GM picks a number, 2-12, for Alani to roll. The GM can gauge the base difficulty this way. (If he wants, he can use the UGM modifiers, modifying the roll starting at 8+, up or down, based on how hard or easy the GM thinks the roll should be.).

Alani is allowed his Computer skill as a DM. Security is allowed their Computer skill as a penalty DM. The GM may assign other DMs as he sees fit.

That's it. The "opposed" part comes with the adding and subtracting of the two Computer skills.

Maybe the GM thinks it's pretty easy to for Alani to download the data normally. Use the UGM as a guide (Difficulty of 8+, -4 for EASY), the GM states that the roll needed is 4+. Alani can use her Computer-2 skill as a DM.

On the other side of the network, Security is furiously working the panel to shut Alani out. That Security Officer's Computer-3 skill will be used as a penlaty on Alani's throw.

So...

Alani ends up throwing this Opposed Throw:

2D +2 -3 for 4+.

2D -1 for 4+.

---------------

Or, if you want to keep the UGM 8+ total on all of your throws, you can express this same roll as:

2D +2 -3 +4 for 8+

2D +3 for 8+.


That's kind of a long winded post to explain a simple idea.

What I like about it is that you're only throwing one throw...throw it, and keep on playing.

-S4

 

[Supplement Four]

As I look at my post, I see that the example I note is weighted in Alani's favor.

What do you do if you want to give both sides of the opposed roll a fair chance?

Simple. Use a target of 7+ on the roll, and only allow Skill for DMs.

Two characters are on opposite sides of a hatch. One is attempting to punch in the code to activate the hatch lock. The other is attempting to code the key pad so the hatch will open.

Roll 2D for 7+. Add and Subtract Computer Skill DMs.

That's it.

Even shake on the roll, weighted only by expertise.

-S4

 

[Supplement Four]

As I look at my post, I see that the example I note is weighted in Alani's favor.

What do you do if you want to give both sides of the opposed roll a fair chance?

Simple. Use a target of 7+ on the roll, and only allow Skill for DMs.

Two characters are on opposite sides of a hatch. One is attempting to punch in the code to activate the hatch lock. The other is attempting to code the key pad so the hatch will open.

Roll 2D for 7+. Add and Subtract Computer Skill DMs.

That's it.

Even shake on the roll, weighted only by expertise.

-S4

 

[Supplement Four]

What if natural ability (stats), and not expertise (skill) is the determining factor of your opposed roll?

Let's say two guys are arm wrestling. Who wins?

Well, we'll base this on STR.

One character in this arm wrestling match has STR-5. The other has STR-10.

The roll is 2D for 7+.

Subtract the two STR scores, then halve them. Drop fractions (so that ability scores must be separated by at least two points to get a DM). That's your DM.

10 - 5 = 5.

5 / 2 = 2.

If the STR-5 character makes this opposed roll, he rolls 2D -2 for 7+.

If the STR-10 character makes this opposed roll, he rolls 2D +2 for 7+.

Simple as that.

-S4

 

[Supplement Four]

What if natural ability (stats), and not expertise (skill) is the determining factor of your opposed roll?

Let's say two guys are arm wrestling. Who wins?

Well, we'll base this on STR.

One character in this arm wrestling match has STR-5. The other has STR-10.

The roll is 2D for 7+.

Subtract the two STR scores, then halve them. Drop fractions (so that ability scores must be separated by at least two points to get a DM). That's your DM.

10 - 5 = 5.

5 / 2 = 2.

If the STR-5 character makes this opposed roll, he rolls 2D -2 for 7+.

If the STR-10 character makes this opposed roll, he rolls 2D +2 for 7+.

Simple as that.

-S4

 

[Supplement Four]

One last thought on this...

To be strictly fair, the person rolling 7+ has a slight advantage.

Why?

Becuase he will fail on: 2, 3, 4, 5, or 6.

He will succeed on: 7, 8, 9, 10, 11, 12.

He has more chances to succeed.

Remedy: Use either 7+, or 8+ as the target number on these types of rolls. And, consider that small advantage when determining who will roll.

Back to the arm wrestling example above. I'd give the advantage to the stronger guy.

So, I'd have the stonger guy roll, rolling 2D +2 for 7+.

If the STR-5 guy is the player character, no problem. Let him roll 2D -2 for 8+.

Consider your rulings like that, and you'll keep your opposed rolls fair.

-S4

 

[Supplement Four]

One last thought on this...

To be strictly fair, the person rolling 7+ has a slight advantage.

Why?

Becuase he will fail on: 2, 3, 4, 5, or 6.

He will succeed on: 7, 8, 9, 10, 11, 12.

He has more chances to succeed.

Remedy: Use either 7+, or 8+ as the target number on these types of rolls. And, consider that small advantage when determining who will roll.

Back to the arm wrestling example above. I'd give the advantage to the stronger guy.

So, I'd have the stonger guy roll, rolling 2D +2 for 7+.

If the STR-5 guy is the player character, no problem. Let him roll 2D -2 for 8+.

Consider your rulings like that, and you'll keep your opposed rolls fair.

-S4

 

[Golan2072]

I like this, with its CT flavor - and i'll add it to the UGM document soon

 

[Golan2072]

I like this, with its CT flavor - and i'll add it to the UGM document soon

 

[ravells]

Very elegant!

Ravs

 

[ravells]

Very elegant!

Ravs

 

[Paulsnow]

Originally posted by Supplement Four:
One last thought on this...

To be strictly fair, the person rolling 7+ has a slight advantage.

But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

 

[Paulsnow]

Originally posted by Supplement Four:
One last thought on this...

To be strictly fair, the person rolling 7+ has a slight advantage.

But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

 

[Stainless]

Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Trust a physicist to throw a spanner in the gravy

I'd have to agree with Paul. And in any case, what's so harmful about throwing two sets of dice? It will probably take as long as to do the above calculations. To my mind, throwing two sets of dice gives the flavour of a competition, so I'd vote for it's use simply for dramatic effect.

 

[Stainless]

Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Trust a physicist to throw a spanner in the gravy

I'd have to agree with Paul. And in any case, what's so harmful about throwing two sets of dice? It will probably take as long as to do the above calculations. To my mind, throwing two sets of dice gives the flavour of a competition, so I'd vote for it's use simply for dramatic effect.

 

[Supplement Four]

Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Au contraier, my little buttercup.

You can have a 50/50 chance of success and a chance for a tie by just rolling a single 2D roll.

It's easy.

Let's say the two wrestlers in my example above were evenly matched--both with STR-9.

Have one of them roll 2D for 8+, and a result of 7 exactly is a tie.

There, you have it. That's an even chance to both sides to succeed, an a 17% chance of a tie to boot.

Roll 2D.

Result of 6- fails.

Result of 7 excatly ties.

Result of 8+ succeeds.

Simple as that.




Typically, though, situations that pop up in a role playing game that require an opposed roll always feature one side advantaged over the other.

In the wrestling example above, it's the stronger wrestler that is advantaged. In the example where two people attempt to open/close that hatch, the advantaged person is the one who starting coding the lock first (in game terms: the one who went first in the round).

One thing that is nice about this one-roll Opposed Roll that I have presented is that a GM can easily skew success when appropriate. (That's a little harder to do when two separate rolls are involved).

For instance, look at the first example I mention above where the guy is trying to download info from the computer and Security is trying to stop him.

With a normal two-roll Opposed Roll, you start with a 50/50 proposition, and then modify it from there with their skills.

This one-roll methods allows the GM, if he wants, to skew the roll. In the example above, I skewed it in the downloader's favor. But, what if, as soon as the unauthorized download is detected, all Security has to do is slap a single button?

In that case, the GM can easily assign a roll: 2D for 10+ to finish downloading the info. Add/Subtract Computer skills from both sides.

Or, think about the example where the two guys are trying to open/close the hatch.

In order to open the hatch, maybe it's just a matter of hitting the green button.

In order to lock the hatch, maybe you've got to hit the red button and then type in your personal code to lock it.

Given this, a GM could easily weight the Opposed Roll in favor of the person opening the hatch, against the person trying to type in a code lock.

Maybe, for this instance: 2D for 4+. Add/Subtract DEX mod.




Another neat thing that is possible with the one roll Opposed roll is that you can do things like comparing Stat and TL.

Let's say a character is trying to pick an old fashioned lock (using lock picks). Use the character's DEX when considering the modifier. Use the Tech Level of the lock when considering the opposing modifier.

So, the GM decides picking the lock is an opposed roll, using DEX and TL, on a roll of 2D for 10+.

Character has DEX-11

Lock is TL-6.

11 - 6 = 5.

5 / 2 = 2.

Picking the lock works out to: 2D +2 for 10+.

Easy.




Or...

Let's say a character needs to diffuse a bomb. The GM decides on using an Opposed Roll.

We start off with a basic 2D for 8+ roll. Then, we use the UGM modifiers to modify that base chance. The GM decides that diffusing this bomb is DIFFICULT, so the base roll is: 2D -2 for 8+.

Use the Demolitions skill for each character to modify the opposed roll. Use the Demolitions skill for the character diffusing the bomb. And, use the Demolitons skills for the character who set the bomb.

Whammo. You've got your Opposed Roll.

Diffuser's skill is Demolitions-1

Setter's skill is Demolitons-3

Base roll is: 2D -2 for 8+ (or 2D for 10+)

Oppossed Roll is: 2D -2 +1 -3 for 8+.

2D -4 for 8+

2D for 12+.

Wouldn't want to be around when that time limit expired.




Bottom line is: Using this Opposed Roll technique, you can adjust your Opposed Roll to refelct the situation (the Advantaged/DisAdvantaged situation).

And, if you need a even chance between both parties, and want a tie possible (like you can have when both sides make a roll), then just use the 2D for 8+ roll with an exact 7 representing a tie.

 

[Supplement Four]

Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Au contraier, my little buttercup.

You can have a 50/50 chance of success and a chance for a tie by just rolling a single 2D roll.

It's easy.

Let's say the two wrestlers in my example above were evenly matched--both with STR-9.

Have one of them roll 2D for 8+, and a result of 7 exactly is a tie.

There, you have it. That's an even chance to both sides to succeed, an a 17% chance of a tie to boot.

Roll 2D.

Result of 6- fails.

Result of 7 excatly ties.

Result of 8+ succeeds.

Simple as that.




Typically, though, situations that pop up in a role playing game that require an opposed roll always feature one side advantaged over the other.

In the wrestling example above, it's the stronger wrestler that is advantaged. In the example where two people attempt to open/close that hatch, the advantaged person is the one who starting coding the lock first (in game terms: the one who went first in the round).

One thing that is nice about this one-roll Opposed Roll that I have presented is that a GM can easily skew success when appropriate. (That's a little harder to do when two separate rolls are involved).

For instance, look at the first example I mention above where the guy is trying to download info from the computer and Security is trying to stop him.

With a normal two-roll Opposed Roll, you start with a 50/50 proposition, and then modify it from there with their skills.

This one-roll methods allows the GM, if he wants, to skew the roll. In the example above, I skewed it in the downloader's favor. But, what if, as soon as the unauthorized download is detected, all Security has to do is slap a single button?

In that case, the GM can easily assign a roll: 2D for 10+ to finish downloading the info. Add/Subtract Computer skills from both sides.

Or, think about the example where the two guys are trying to open/close the hatch.

In order to open the hatch, maybe it's just a matter of hitting the green button.

In order to lock the hatch, maybe you've got to hit the red button and then type in your personal code to lock it.

Given this, a GM could easily weight the Opposed Roll in favor of the person opening the hatch, against the person trying to type in a code lock.

Maybe, for this instance: 2D for 4+. Add/Subtract DEX mod.




Another neat thing that is possible with the one roll Opposed roll is that you can do things like comparing Stat and TL.

Let's say a character is trying to pick an old fashioned lock (using lock picks). Use the character's DEX when considering the modifier. Use the Tech Level of the lock when considering the opposing modifier.

So, the GM decides picking the lock is an opposed roll, using DEX and TL, on a roll of 2D for 10+.

Character has DEX-11

Lock is TL-6.

11 - 6 = 5.

5 / 2 = 2.

Picking the lock works out to: 2D +2 for 10+.

Easy.




Or...

Let's say a character needs to diffuse a bomb. The GM decides on using an Opposed Roll.

We start off with a basic 2D for 8+ roll. Then, we use the UGM modifiers to modify that base chance. The GM decides that diffusing this bomb is DIFFICULT, so the base roll is: 2D -2 for 8+.

Use the Demolitions skill for each character to modify the opposed roll. Use the Demolitions skill for the character diffusing the bomb. And, use the Demolitons skills for the character who set the bomb.

Whammo. You've got your Opposed Roll.

Diffuser's skill is Demolitions-1

Setter's skill is Demolitons-3

Base roll is: 2D -2 for 8+ (or 2D for 10+)

Oppossed Roll is: 2D -2 +1 -3 for 8+.

2D -4 for 8+

2D for 12+.

Wouldn't want to be around when that time limit expired.




Bottom line is: Using this Opposed Roll technique, you can adjust your Opposed Roll to refelct the situation (the Advantaged/DisAdvantaged situation).

And, if you need a even chance between both parties, and want a tie possible (like you can have when both sides make a roll), then just use the 2D for 8+ roll with an exact 7 representing a tie.

 

[Paulsnow]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Au contraier, my little buttercup.

You can have a 50/50 chance of success and a chance for a tie by just rolling a single 2D roll.

It's easy.

Let's say the two wrestlers in my example above were evenly matched--both with STR-9.

Have one of them roll 2D for 8+, and a result of 7 exactly is a tie.

There, you have it. That's an even chance to both sides to succeed, an a 17% chance of a tie to boot.

Roll 2D.

Result of 6- fails.

Result of 7 excatly ties.

Result of 8+ succeeds.

Simple as that.</font>[/QUOTE]That is a fine refinement. The tie can represent that the opponents exactly cancel themselves out (nil-nil after extra time) or that the struggle has to continue after the first interaction (perhaps, comabt round).

Typically, though, situations that pop up in a role playing game that require an opposed roll always feature one side advantaged over the other.

I'm not sure that I generally agree with this in terms of realism. It seems to be granting a special advantage to the initiator of a situation. However, it is probably good for keeping an RPG flowing along.

In the wrestling example above, it's the stronger wrestler that is advantaged.

But the advantage should come from the strength not from the fact that he started the arm wrestling.

Your examples are neat and it is a good quick system.

However, I think it practice that some players would feel hard done by if they blew themselves up because they were rolling blind against a much more skilled adversary. (e.g your demolitions example). This is where an evaluate-situation use of the skill paired with Int would tell them what they are getting into. Of course, the naive (poorly skilled) would be worse at evaluating the scale of the problem they are facing.

Keep up the good work! (Sorry: that sounds patronising - but my buttercupness couldn't restrain it)

 

[Paulsnow]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by Paul Snow:
But what about two equally matched arm wrestlers, football teams or chess payers. If they are equally matched the outcome should be 50/50 between them.(To me, BTW, that defines equally matched.)

The one roll sytem can't do that on 2D as there isn't a 50/50 point in the probablities although there is with 3d IIRC.

A 2-roll system can have 50/50 chance of success and also a chance for a tie.

Au contraier, my little buttercup.

You can have a 50/50 chance of success and a chance for a tie by just rolling a single 2D roll.

It's easy.

Let's say the two wrestlers in my example above were evenly matched--both with STR-9.

Have one of them roll 2D for 8+, and a result of 7 exactly is a tie.

There, you have it. That's an even chance to both sides to succeed, an a 17% chance of a tie to boot.

Roll 2D.

Result of 6- fails.

Result of 7 excatly ties.

Result of 8+ succeeds.

Simple as that.</font>[/QUOTE]That is a fine refinement. The tie can represent that the opponents exactly cancel themselves out (nil-nil after extra time) or that the struggle has to continue after the first interaction (perhaps, comabt round).

Typically, though, situations that pop up in a role playing game that require an opposed roll always feature one side advantaged over the other.

I'm not sure that I generally agree with this in terms of realism. It seems to be granting a special advantage to the initiator of a situation. However, it is probably good for keeping an RPG flowing along.

In the wrestling example above, it's the stronger wrestler that is advantaged.

But the advantage should come from the strength not from the fact that he started the arm wrestling.

Your examples are neat and it is a good quick system.

However, I think it practice that some players would feel hard done by if they blew themselves up because they were rolling blind against a much more skilled adversary. (e.g your demolitions example). This is where an evaluate-situation use of the skill paired with Int would tell them what they are getting into. Of course, the naive (poorly skilled) would be worse at evaluating the scale of the problem they are facing.

Keep up the good work! (Sorry: that sounds patronising - but my buttercupness couldn't restrain it)