Section 1 - Basics

The Basics

GURPS: Stellar Winds uses six-sided dice only. To figure combat damage (and several other things), the “dice+adds” system is used. If a weapon does “4d+2” damage, this is shorthand for “roll 4 dice and add 2 to the total.” Likewise, “3d-3” means “roll 3 dice and subtract 3 from the total.” If you see just “2d,” that means “roll two dice.” This system has only three basic “game mechanics”: success rolls, reaction rolls, and damage rolls.

Success Rolls


A “success roll” is a die roll made when you need to “test” one of your skills or abilities. Sometimes you roll; sometimes the GM rolls for you. For instance, you might test, or roll against, your Strength to stop a heavy door from closing.

What to Roll

Whenever a character attempts to perform an action (e.g., use a skill), roll three dice to determine the outcome. This is called a success roll. The task in question succeeds if the total rolled on the dice is less than or equal to the number that governs the action – most often a skill or an attribute. Otherwise, it fails. For example, if you are rolling against Strength, and your ST is 12, a roll of 12 or less succeeds. Thus, the higher the stat you are rolling against, the easier it is to make the roll.Whenever a character attempts to perform an action (e.g., use a skill), roll three dice to determine the outcome. This is called a success roll. The task in question succeeds if the total rolled on the dice is less than or equal to the number that governs the action – most often a skill or an attribute. Otherwise, it fails. For example, if you are rolling against Strength, and your ST is 12, a roll of 12 or less succeeds. Thus, the higher the stat you are rolling against, the easier it is to make the roll. Regardless of the score you are rolling against, a roll of 3 or 4 is always a success, while a roll of 17 or 18 is always a failure. In general, the player makes the die rolls for his character’s actions. However, the GM may always choose to roll the dice in secret – see When the GM Rolls, below.

Regardless of the score you are rolling against, a roll of 3 or 4 is always a success, while a roll of 17 or 18 is always a failure. In general, the player makes the die rolls for his character’s actions. However, the GM may always choose to roll the dice in secret – see When the GM Rolls, below.

When to Roll

To avoid bogging down the game in endless die rolls, the GM should only require a success roll if …

  • A PC’s health, wealth, friends, reputation, or equipment are at risk. This includes chases, combat (even if the target is stationary and at point-blank range!), espionage, thievery, and similar "adventuring activities."
  • A PC stands to gain allies, information, new abilities, social standing, or wealth.

The GM should not require rolls for…

  • Utterly trivial tasks, such as crossing the street, driving into town, feeding the dog, finding the corner store, or turning on the computer.
  • Daily work at a mundane, non-adventuring job.

When the GM Rolls

There are two sets of circumstances under which the GM should roll for a PC and not let the player see the results:
1. When the character wouldn’t know for sure whether he had succeeded.
2. When the player shouldn’t know what’s going on.

Modifiers

The rules often specify modifiers for certain success rolls. These bonuses and penalties affect the number you are rolling against – your “target number” – and not the total rolled on the dice. Bonuses always improve your odds, while penalties always reduce them.

For instance, when using the Lockpicking skill in the dark, the GM might tell you to roll at -5 for the attempt. If your Lockpicking skill is 9, you roll against 9 minus 5, or 4, in the dark.

A specific scenario might provide modifiers to allow for the relative ease or difficulty of a particular situation. For instance, an adventure might state that a lock is +10 to open due to the fact that it is primitive and clumsy. If your Lockpicking skill were 9, you would roll against 9 + 10, or 19. Since the highest roll possible on 3d is 18, it would seem that success is assured. Not quite – see Critical Success and Failure, below

Modifiers are cumulative unless stated otherwise. For instance, if you tried to open that primitive lock in the dark, both modifiers would apply, and you would roll against 9 - 5 + 10, or 14.

Base Skill vs Effective Skill

Your base skill is your actual level in a skill, as recorded on your character sheet. Your effective skill for a particular task is your base skill plus or minus any modifiers for that task. In the Lockpicking examples above, the base skill is 9 in all cases, while the effective skill is 4, 19, or 14.

You may not attempt a success roll if your effective skill is less than 3 unless you are attempting a defense roll.

Degree of Success or Failure

Once you have calculated your effective skill by applying all the relevant modifiers to your base skill, roll 3d to determine the outcome. If the total rolled on the dice is less than or equal to your effective skill, you succeed, and the difference between your effective skill and your die roll is your margin of success. Example: If you have effective skill 18 and roll a 12, you succeed; your margin of success is 6.

If you roll higher than your effective skill, you fail, and the difference between the die roll and your effective skill is your margin of failure.

Example: If you have effective skill 9 and roll a 12, you fail; your margin of failure is 3.

Many rules use margin of success or failure to calculate results that matter in play, so be sure to note it when you roll.

Critical Success and Failure

A critical success is an especially good result.

• A roll of 3 or 4 is always a critical success.
• A roll of 5 is a critical success if your effective skill is 15+.
• A roll of 6 is a critical success if your effective skill is 16+.

When you roll a critical success, the GM determines what happens. It is always something good! The lower the roll, the better “bonus” he gives you.

A critical failure is an especially bad result.

• A roll of 18 is always a critical failure.
• A roll of 17 is a critical failure if your effective skill is 15 or less; otherwise, it is an ordinary failure.
• Any roll of 10 or more greater than your effective skill is a critical failure: 16 on a skill of 6, 15 on a skill of 5, and so on.

When you roll a critical failure, the GM determines what happens. It is always something bad – the higher the roll, the worse the result.

Repeated Attempts

Sometimes you only get one chance to do something (defuse a bomb, jump over a crevasse, remove an inflamed appendix, please the King with a song). Other times you can try over and over again until you succeed (pick a lock, catch a fish, analyze a poison). Still other times you will not know whether you succeeded or failed until it’s too late to try again (translate an old treasure map, order in a French restaurant, build a ship). Finally, there are times when you are injured by failure but can afford to fail a few times (climb a wall, impress a savage tribesman).

The GM must use common sense to distinguish among these cases, according to the exact situation in which the adventurers find themselves.

Contents

Sometimes a situation arises in which two characters must compare attributes, skills, or other traits to settle a competition. The one with the highest score doesn’t always win … but that’s the way to bet. A “Contest” is a quick way to handle such a competitive situation without playing it out in detail. In a Contest, each competitor attempts a success roll against the ability being tested – with all applicable modifiers – and then compares his result to his opponent’s. There are two different ways to make this comparison.

Quick Contest

A “Quick Contest” is a competition that is over in very little time – often in one second, perhaps even instantly. Examples include two enemies lunging for a gun or
two knife throwers seeing who gets closer to the bull’s-eye. Each competitor attempts his success roll. If one succeeds and the other fails, the winner is obvious. If both succeed, the winner is the one with the largest margin of success; if both fail, the winner is the one with the smallest margin of failure. A tie means nobody won (in the examples above, both fighters grabbed the weapon at once, or the knives hit the same distance from the bull’s-eye).

Margin of Victory

The amount by which the winner beat the loser is often important – success by 5 vs. failure by 5 generally means more than success by 2 vs. success by 1! The winner’s “margin of victory” is the difference between his margin of success and the loser’s margin of success if both succeeded, the sum of his margin of success and the loser’s margin of failure if he succeeded and the loser failed, or the difference between the loser’s margin of failure and his margin of failure if both failed.

Regular Contest

A “Regular Contest” is a slow competition with much give and take – for instance,
arm wrestling. Each character attempts his success roll. If one succeeds and the other fails, the winner is obvious. If both succeed or both fail, the competitors’ relative positions are unchanged and they roll again. Eventually, one character succeeds when the other fails. At this point, the one who made his roll is the winner. The length of game time each attempt takes depends on the activity, and is up to the GM. In a combat situation, each attempt takes one second … but in a library-research contest, with the fate of the world hanging on who finds a certain obscure reference first, each attempt could represent days of time.

Reaction Rolls


When the PCs meet an NPC whose reaction to them is not predetermined (see below), the GM makes a “reaction roll” on 3d. The higher the roll, the better the reaction. The GM then plays the NPC according to the guidelines on the Reaction Table. The GM should keep this roll secret from the players. They don’t know, for instance, whether that friendly-looking old farmer is giving them straight advice or sending them into a trap.

A reaction roll is not a success roll. There are three important differences:

1.) There is no "target number" to roll against.
2.) A High roll is good, not bad
3.) Reaction modifiers apply directly to the die roll. A reaction bonus is any factor that makes NPC friendlier, while a reaction penalty is something that biases NPCs against the PCs.

Some common reaction modifiers:

Personal appearance and behavior: This is especially true for the PC who does the talking! Above-average appearance gives a bonus, as do some advantages (see p. 8). Below-average appearance and many disadvantages give a penalty.

Racial or national biases: Elves don’t like dwarves, Frenchmen don’t care for Germans, and so on. These are usually penalties, and take the form of an Intolerance disadvantage on the part of the NPC.

Appropriate behavior by the players: Here’s a chance to reward good roleplaying. A good approach should be worth +1 or more! A wholly inappropriate approach that antagonizes the NPCs should give the party -1 or -2 on the reaction roll. Don’t tell the players, “You blew it!” – just roleplay the offended character, and let them figure it out.

Random reaction rolls are great when they add a note of unpredictability to the game – this is more fun for the GM, too! However, never substitute random die rolls for reason and logic.

Reaction Table

Roll 3 dice and apply any reaction modifiers.

0 or less: Disastrous: The NPC hates the characters and will act in their worst interest. Nothing is out of the question: assault, betrayal, public ridicule, or ignoring a life-or death plea are all possible.

1 to 3: Very Bad: The NPC dislikes the characters and will act against them if it’s convenient to do so: attacking, offering grossly unfair terms in a transaction, and so on.

4 to 6: Bad: The NPC cares nothing for the characters and will act against them (as above), if he can profit by doing so.

7 to 9: Poor: The NPC is unimpressed. He may make threats, demand a huge bribe before offering aid, or something similar.

10 to 12: Neutral: The NPC ignores the characters as much as possible. He is totally uninterested. Transactions will go smoothly and routinely, as long as protocol is observed.

13 to 15: Good: The NPC likes the characters and will be helpful within normal, everyday limits. Reasonable requests will be granted.

16 to 18: Very Good: The NPC thinks highly of the characters and will be quite helpful and friendly, freely offering aid and favorable terms in most things.

19 or better Excellent: The NPC is extremely impressed by the characters, and will act in their best interests at all times, within the limits of his own ability – perhaps even risking his life, wealth, or reputation.

Damage Rolls

“damage roll” is a roll made in a fight, to see how much harm you did to your foe. Damage rolls use the “dice+adds” system. Many things can affect the final injury inflicted by your attack. Armor reduces the damage received by the wearer. Certain attacks do extra damage if they get through armor. All these things are explained in the combat rules.

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