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While polyhedral dice had previously been used in teaching basic arithmetic, the fantasy role-playing game Dungeons & Dragons* is largely credited with popularizing their use in roleplaying games. Some games use only one type,  while others use numerous types for different game purposes, such as Dungeons & Dragons, which make use of 20-, 12-, 10-, 8- and 4-sided dice in addition to the traditional 6-sided die. Unlike the common six-sided die, these dice often have the numbers engraved on them rather than a series of dots. OpenCore® game rules use the six-sided and twelve sided dice for most of the combat and saving throws.

OpenCore® games generally use dice to determine the outcome of events, such as the success or failure of actions which are difficult to perform. A player may have to roll dice for combat, skill use,  amongst other things, generally referred to as a "check". This is generally considered fairer than decision by the game master, since success and failure are decided randomly based on a flat probability. OpenCore® games typically determine success as either a total on one or more dice above  or below  a target number, or a certain number of rolls above a certain number (such as 8 or higher on a d1e) on one or more dice. The player may gain a bonus or penalty due to circumstances or character skill, usually either by a number added to or subtracted from the final result, or by having the player roll extra or fewer dice. For example, a character trying to climb a sheer wall may subtract from their dice roll (known as a penalty) if the wall is slippery, which simulates the increased difficulty of climbing a slick or slippery surface, while a character using a rope may add to the roll (known as a bonus) to simulate that the rope makes the act of climbing easier.

Dice can also be used by a game master for other purposes, such as to randomly generate game content or to make arbitrary decisions. OpenCore® uses dice to determine what attributes the player's character has when created, such as how strong he or she is.

In Dungeons & Dragons and some other roleplaying games which use more than one kind of die, dice notation is used for clarity and conciseness. For example, a six-sided die is referred to as a d6, and the notation for rolling two such dice is 2d6. A constant bias may be added or subtracted by ordinary arithmetic: for example, 2d6+4 adds a 4 point bonus, while 2d6-2 subtracts a 2 point penalty. Games which use only one type of dice rarely require complex dice notation.

A common special case is percentile rolls, referred to in dice notation as 1d100 or 1d%. Since actual hundred-sided dice are large, almost spherical, and difficult to read, percentile rolls are usually handled by rolling two ten-sided dice together, using one as the "tens" and the other as the "units". A roll of ten or zero on either die is taken as a zero, unless both are zeros or tens, in which case this is 100 (rather than zero). To avoid this confusion, some sets of percentile dice exist where one is marked in tens (00, 10, 20... up to 90) and the other from 0 to 9. White and black percentile dice are also used, and are commonly found in color-coded dice sets, or sold separately.

Dice for role-playing games are usually made of plastic, though infrequently metal, wood, and semi-precious stone dice can be found. Early polyhedral dice from the 1970s and 1980s were made of a soft plastic that would easily wear as the die was used. Typical wear and tear would gradually round the corners and edges of the die until it was unusable. Many early dice were unmarked and players took great care in painting their sets of dice. Some twenty-sided dice of this era were numbered zero through nine twice; half of the numbers had to be painted a contrasting color to signify the "high" faces. Such a die could also double as a ten-sided die by ignoring the distinguishing coloring.

Probability

By Tom Ramsey used with permission.

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How do I play this game? Just What is a Role-playing game?

A role-playing game (RPG) is a broad family of games in which players assume the roles of characters, or take control of one or more avatars, in a fictional setting. Actions taken within the game succeed or fail according to a formal system of rules and guidelines.

The original form, sometimes called the pen-and-paper RPG, is conducted through speech. In live action role-playing games (LARP), players perform their characters' physical actions.  In both of these forms, an arranger called a game master (GM) usually decides on the rules and setting to be used and acts as referee, while each other player plays the role of a single character.  At the heart of these formats is in-character participation in a collaborative narrative.

Role playing games are fundamentally different from most other types of games in that they stress social interaction and collaboration not competition.

OpenCore® games are a form of interactive and collaborative storytelling.  However, it is not considered a true narrative like novels or films as there is no actual story within a role-playing game. Instead events, characters and narrative structure give a sense of a narrative experience. Like stories, role-playing games appeal because they engage the imagination. Interactivity is the crucial difference between role-playing games and traditional fiction. Whereas a viewer of a television show is a passive observer, a player at a role-playing game makes choices that affect the story. Such  games extend an older tradition of storytelling games where a small party of friends collaborate to create a story.

While simple forms of role-playing exist in traditional children's games such as "cops and robbers" and "cowboys and Indians", role-playing games add a level of sophistication and persistence to this basic idea with the addition of numeric rule sets and the participation of a referee. Participants in a role-playing game will generate specific characters and an ongoing plot. A consistent system of rules and a more or less realistic campaign setting in games aids suspension of disbelief. The level of realism in games ranges from just enough internal consistency to set up a believable story or credible challenge up to full-blown simulations of real-world processes.

OpenCore® games are conducted through speech in a small social gathering. The GM describes the game world and its inhabitants. The other players describe the intended actions of their characters, and the GM describes the outcomes.  Some outcomes are determined by the game system, and some are chosen by the GM.

In a OpenCore® game the Game-master's purpose is to weave the other participants' player-character stories together, control the non-player aspects of the game, and create environments in which the players can interact.

OpenCore® role-playing games are conducted like radio drama : only the spoken component is acted or described in detail. In most games, one specially designated player, the game master  (GM), creates a setting  in which each player plays the role of a single character . The GM describes the game world and its inhabitants; the other players describe the intended actions of their characters, and the GM describes the outcomes. Some outcomes are determined by the game system, and some are chosen by the GM.

The GM will begin the game with a short introduction which introduces the setting and the characters. The players describe their characters' actions, and the GM responds by describing the outcome of those actions. Usually, these outcomes are determined by the setting and the GM's common sense; most actions are straightforward and immediately successful. For example, if a player has their character look around a room, the GM will describe the room; if they have their player leave, the GM will describe whatever they encounter outside the room. However, the outcomes of some actions are determined by the rules of the game. This usually involves rolling dice and comparing the number rolled to their character's statistics to see whether the action was successful.

The game continues in this manner until the characters meet the last challenge, as determined by the GM at the start of the game. This could be to defeat a specific adversary, solve a mystery, or find a specific item of treasure. The GM then describes the consequences of their actions on the game world, and the game ends.

1.0 Character creation

Player Character's or PC's are the central focus in the game. Each player must create a persona to 'role play' during the game session. All PC's begin the game around the age of twenty-two years of age. It is assumed that a four year advanced education has been obtained at a University.
Each player creates  his or her player character and records the details  on a record sheet provided. First, a player determines his or her character's ability scores , which consist of Strength, Agility, Constitution, Dexterity, Intelligence, Perception, Wisdom, Comeliness and Charisma.

ABILITY SCORES

Roll a 1d100 for each ability. Range 1 - 100.

Strength  (STR):

Strength is a measure of muscle, endurance and stamina combined. Strength affects the ability of characters to lift and carry weights, melee attack rolls, damage rolls (for both melee and ranged weapons,) the Jump, Climb, and Swim skills, several combat actions, and general checks involving moving or breaking stubborn objects.

Dexterity (DEX):

Fine motor skills are the coordination of small muscle movements which occur e.g., in the fingers, usually in coordination with the eyes.

Agility (AGL):

This attribute is used when speed, or grace are required. Actions using Agility might include running quickly, dodging a falling rock or swerving to avoid a car crash. The quality of being agile; the power of moving the limbs quickly and easily; nimbleness; activity; quickness of motion; as, strength and agility of body and encompasses a number of physical attributes including hand-eye coordination, agility, reflexes, fine motor skills, balance and speed of movement; a high agility score indicates superiority in all these attributes. AGL affects characters with regard to initiative in combat, ranged attack rolls, Armor Class, Reflex saves, and the Balance, Escape Artist, Hide, Move Silently, Open Lock, Ride, Sleight of Hand, Tumble, and Use Rope skills. It also affects the number of additional attacks of opportunity granted by the Combat Reflexes feat. Dexterity is the ability most influenced by outside influences (such as armor).

Constitution  (CON):

Constitution is a term which encompasses the character's physique, toughness, health and resistance to disease and poison. The higher a character's Constitution, the more hit points that character will have. Constitution also is important for Fortitude saves, the Concentration skill, and fatigue-based general checks. Constitution also determines the duration of a barbarian's rage. Unlike the other ability scores, which render the character unconscious or immobile when they hit 0, having 0 Constitution is fatal.

Intelligence  (INT):

Intelligence is similar to IQ, but also includes mnemonic ability, reasoning and learning ability outside those measured by the written word. Intelligence dictates the number of languages a character can learn. It also affects how many skill points a character gains per level, the Appraise, Craft, Decipher Script, Disable Device, Forgery, Knowledge, Search.

Perception  (PER):

Perception  is the attribute which governs a character’s alertness and awareness. Examples of using Perception are hearing faint running footsteps, noticing an unusual rock or memorizing a car’s number plate as it speeds away from an accident.

Perception (plural perceptions)

1. Conscious understanding of something.

2. Vision (ability)

3. Acuity

4.  (Cognition) That which is detected by the five senses; not necessarily understood (imagine looking through fog, trying to understand if you see a small dog or a cat); also that which is detected within consciousness as a thought, intuition, deduction, etc.

 To succeed at a Perception roll the PC must roll a 1d100 higher than the PER score.

Wisdom  (WIS):

Wisdom is a composite term for the characters enlightenment, judgment, wile, willpower and intuitiveness. It  affects Will saving throws, Listen, Profession, Sense Motive, Spot, and Survival skills.

Charisma  (CHA):

Charisma is the measure of the character's combined physical attractiveness, persuasiveness, and personal magnetism. A generally non-beautiful character can have a very high charisma due to strong measures of the other two aspects of charisma. It affects Bluff, Diplomacy, Disguise, Gather Information, Handle Animal, Intimidate.

Comeliness (COM):

Comeliness (COM): Is the differentiate between physical attractiveness and Charisma. Physical attractiveness is the perception of the physical traits of an individual human person as aesthetically pleasing or beautiful , and can include various implications such as sexual attractiveness and physique. 

*If the CHA score is low ( less than 50) then add 25 to the COM score. If the CHA is 51 or higher than subtract 25 from the COM score.* Note a COM score cannot be more than 100.

CHARACTER COMPOSITE SCORE
In order to move the game along and to make task resolution more efficient a system using a composite score instead of using the nine ability scores in every situation.

Strength, Dexterity, Agility and Constitution are added up and divided by four to create the ADAC composite score.

Intelligence, Perception and Wisdom are added up and divided by three to create the IPW composite score.

Charisma, Comeliness are added up and divided by two to create the CC composite score.

For example:

Buck Hunter 1st level SAD / SOG Player Character.

STR: 76

DEX: 80

AGL: 21

CON: 32 SDAC score = 52

______________________________________________________________

INT: 86

PER: 96

WIS: 32 IPW score = 71

______________________________________________________________

CHA: 17

COM: 92 CC score =59  See rule for CHA.

SAVING THROWS

There are five kinds of Saving Throws:

Physical Toughness : [SDAC score or better on a 1d100-CON.]

  A PT save represents, incorporating, fortitude, stamina, ruggedness, physique, bulk, metabolism, resistance, immunity, and other similar physical qualities. Fortitude saves involve a character's resistance to an effect that directly attacks his health, stamina. This includes resisting poison, and ignoring horrible. Typically, Fortitude saves are the sort of thing that a "tough guy" would be good at. Fortitude saves are affected by the Constitution base stat.

Reflex : [SDAC score or better on a 1d100-DEX.]

  A Reflex save represents physical (and sometimes mental) agility, incorporating quickness, nimbleness, hand-eye coordination, overall coordination, speed, and reaction time. Reflex saves involve a character's ability to move out of the way of an incoming object or his ability to leave an area in a short amount of time. This includes the character's ability to dodge falling rocks. Typically, Reflex saves are the sort of thing that an agile person would be good at. Reflex saves are affected by the Dexterity base stat.

Willpower : [SDAC score or better on a 1d100-WIS.]

  A Will save represents inner strength, incorporating willpower, mental stability, the power of the mind, levelheadedness, determination, self-confidence, the superego, and resistance to temptation. Will saves involve a character's mental resistance to mental dominance, confusion, stress, and insanity. This includes the character's ability to resist a torture, and to resist supernatural fear. Typically, Will saves are the sort of thing that a confident or determined person would be good at. Will saves are affected by the Wisdom base stat.

Awareness: [IPW roll 1d100 or less to be successful]

 Awareness is usually rolled by 'The Director,' (or Game Master) to see if a character spots something at least partially hidden, or

unobtrusive. This is not a learned skill but one that is acquired by experience in the military special operations.

 

Concentration:[IPW roll 1d100 or less to be successful]

  Attention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things.

HEALTH POINTS  (HP):

Health points are a measure of a character's vitality or health; they are determined by the character's class (certain occupations breed hardier people) or race, and Constitution score. Health points are reduced whenever a character takes damage. Typically beings fall unconscious at 0 HP. Living creatures reduced to negative HP's continue to lose additional HPs due to bleeding, etc. unless they are stabilized by chance or healing. When a PC's hit points reach a negative total equal to its Constitution score, it dies."

 All OSS character's start with a HP as determined by the roll of a 1d100 - CON score. This is the base score. You cannot increase your total HP.

Example: Our PC “Buck” rolls a (1d100 - CON)  96-32= 64 HP for Buck.

Fortitude
Fortitude is courage in the face of adversity. Characters have a Fortitude score based on Constitution:

Subtract the appropriate fortitude score from incoming damage dice before rolling them. Treat any result of less than 1 as 1 unless the character has twice as much fortitude as the unmodified number of damage dice.

Time

The combat mechanic is turn-based and operates in rounds. A round is a discrete time interval (approximately 5 seconds) in which all involved parties act in the combat. The order in which parties involved in the combat act is determined by Initiative.
 

Initiative (Group)

In OpenCore® , a character's initiative is a statistic  (either derived or not) which determines the order in which player characters  take actions, especially during combat  or other forms of conflict resolution.

Procedure:

1. Both opposing forces or parties roll a 1d6.

2. The party with the higher score gets first swing or desires to hide or simply go away.

3. If the party with initiative chooses to attack combat begins.

Individual Initiative

Players roll 1d20 then add their Dexterity modifier and Weapon speed to determine their Initiative score. The highest score gets to act first in the Action phase. Weapon speed is described below.

Action

Characters may make a single action per combat round. Actions include movement, use of a Power, use of a skill, bide, attack and defense.

Movement: Character can move ten feet per action.

(Fantasy rules only) Powers: Character can use one of his Powers. If the power is a touch-based attack, it is assumed that the character attacks at the same time.

Skills: Character can use one of his skills. Many skills are unsuited to combat and the GM can apply penalties to the skill's success roll.

Bide: Character is preparing to act. Next round he gets a +20 bonus to his Initiative roll.

Attack: Character uses one of his attack skills against opponent.

Defense: Character is focusing on defense until his next action - defensive skills are doubled.

Hitting the Enemy

When an attack is made using attack skills or Physical Powers, we compare the numbers. Mental Powers operate differently - see below.

The attacker rolls 1d100 and adds it to the combat skill he is using. In the case of touch-based Powers, use the Hand-to-Hand combat skill. Applicable bonuses are added as well. Statistic modifiers are NOT added, since they are already factored in to the relevant skills. In the case of Physical Powers which are not touch based, the Power's score is used as the combat skill.

The defender rolls 1d100 and adds it to the defense skill he is using. Evade is the most useful, but it is possible to use other skills, such as Acrobatics. Applicable bonuses are added as well, though once again statistic modifiers are not added.

The two totals are compared, and the higher number wins. If it is the attacker, the hit was made and damage needs to be determined. If it is the defender, the attack was not successful and no damage was dealt.

1d100 +attack skill & bonuses vs. 1d100 +defense skill & bonuses

Mental powers used in combat cannot be blocked, though they can be lessened or negated with Magic Resistance. If a character has Magic Resistance, they can effectively ignore any Mental Power with a score below their Magic Resistance. Read the entry for Magic Resistance in the Powers section for more detail.

mental power - magic resistance = power's effective score

Fumbling

If either of the characters rolls 01-05, this is considered a Fumble. When an attacker fumbles, he automatically misses his target. When a defender fumbles, he is automatically hit. In either case, a roll on the Fumble Chart is required:

Fumble Chart

01-60  Attacker/defender recovers from fumble.

61-80   Attacker/defender stumbles, -20 to defense until next turn

81-90   Attacker/defender falls over - opponent gets an immediate extra attack

91-95   Attacker drops weapon and injures self with it

Defender zigs when he should have zagged - takes double damage

96-100   Attacker drops weapon and injures self with it - double damage

Defender zigs when he should have zagged - takes triple damage

Damage

If an attack or Power is successful, damage is dealt. Any Power capable of doing damage describes how much damage it does in the Powers section. Weapons do damage based on weapons class - all weapons will fall into one of the major categories. It is possible for a weapon to be better than the average weapon of its class, but this is up to the GM and is simply a bonus applied to the specific weapon. Some Powers (like Armor and Shielding) prevent some forms of damage.

Damage is subtracted first from Toughness, then from Hit Points. Once Hit Points reach zero, the character has died and must wait a day of game time to regenerate. It is possible to regenerate badly - a regeneration chart can be found in the Running the Game Section.

Armor & Damage Reduction

As expressed above, damage can be reduced by using Powers like Armor and Shielding. Characters can also wear conventional armor to prevent physical damage. Physical armor works like Toughness. All armor is given an armor rating and can take that much damage before it is useless. A character wearing armor would first lose points from the armor, then from Toughness, then from Hit Points.

 

Since armor restricts movement, wearing armor implies a penalty to Initiative. The table below shows the amount of damage armor can take before being rendered useless and the Initiative penalty.

 

Armor  Damage Rating  Initiative Penalty  Description

Leather Armor  25  -5  Leather, either thick or hardened.

Chain Mail  40  -10  Small, linked chain woven together to         form a shirt, or coif, or similar.

Metal Plate  75  -30  Solid plate shaped to fit the body,         jointed at appropriate places.

Kevlar Vest  50  -5  "Bullet proof" vest.

Plated Vest  85  -10  A vest sewn with light, hardened plates.

Police Riot Gear 100  -15  Heavy bullet-proof body armor, boots,         gloves & helmet.

Military PPE  150  -20  Personal Protection Equipment - similar        to riot gear but stronger.

Critical Hits

Critical Hits are rolled whenever damage is done to Hit Points. Damage is done to Hit Points after Toughness has been depleted or in special cases, like being hit with something the character has a substance flaw against. If a critical is rolled while the character still has Toughness left, the amount of Toughness is used as a negative modifier for the critical.


Which table is used depends on the weapon type. Certain weapons and Powers have bonuses or penalties to their critical hits. Crits are rolled using 1d100 and adjusting for bonuses and penalties.


If the unmodified attack roll (1d100) at the beginning of the attack was less than 20 the strike was weak and a -20 penalty is applied to the critical hit roll. If the unmodified attack roll at was greater than 80, the strike was very effective and a +20 bonus is applied to the critical hit roll.

Terminology

Stun: unable to attack, -50 to defense rolls

Unconscious: unable to attack, defend, move or use Powers

Bloodloss: -1 HP loss per round

Slash - Impact - Puncture - Shrapnel - Burn

Slash Critical (blades, claws)

-19 to -10 no extra damage

-9 to 0  no extra damage

0 to 10  no extra damage

11 to 20  no extra damage

21 to 30  no extra damage

31 to 40  no extra damage

41 to 50  +5 damage

51 to 60  +5 damage

61 to 70  +10 damage

71 to 80  +10 damage, bloodloss

81 to 90  +15 damage, bloodloss

91 to 100  +15 damage, stun 1 rounds, bloodloss

101 to 110  +20 damage, stun 2 rounds, bloodlossx2

111 to 120  +20 damage, stun 2 rounds, bloodloss, location severed, -40 to applicable skills

 

Impact Critical (falls, fists, clubs)

-19 to -10  no extra damage

-9 to 0  no extra damage

0 to 10  no extra damage

11 to 20  no extra damage

21 to 30  no extra damage

31 to 40  no extra damage

41 to 50  no extra damage

51 to 60  no extra damage

61 to 70  +5 damage

71 to 80  +5 damage, stun 1 round

81 to 90  +10 damage, stun 2 rounds

91 to 100  +10 damage, stun 2 rounds, location broken, -30 to applicable skills

101 to 110  +15 damage, stun 3 rounds, location broken, -30 to applicable skills

111 to 120  +15 damage, unconscious 1 round

 

Puncture Critical (bullets, spears, stakes)

-19 to -10  no extra damage

-9 to 0  no extra damage

0 to 10  no extra damage

11 to 20  no extra damage

21 to 30  no extra damage

31 to 40  no extra damage

41 to 50  no extra damage

51 to 60  +5 damage

61 to 70  +10 damage

71 to 80  +15 damage

81 to 90  +20 damage, bloodloss

91 to 100  +20 damage, bloodloss

101 to 110  +25 damage, bloodloss, stun 1 round

111 to 120  +25 damage, bloodloss, stun 1 round, location damaged, -20 to applicable skills

 

Shrapnel Critical (grenades, shotguns)

-19 to -10  no extra damage

-9 to 0  no extra damage

0 to 10  no extra damage

11 to 20  +5 damage

21 to 30  +5 damage

31 to 40  +10 damage

41 to 50  +10 damage, bloodloss

51 to 60  +15 damage, bloodloss

61 to 70  +15 damage, bloodloss, stun 1 round

71 to 80  +20 damage, bloodloss, stun 1 round

81 to 90  +20 damage, bloodloss x2, stun 1 round, location damaged -20 to applicable skills

91 to 100  +30 damage, bloodloss x2, stun 2 rounds, location damaged -20 to applicable skills

101 to 110  +40 damage, bloodloss x3, unconscious 1 round, location destroyed -40 to applicable skills

111 to 120  +50 damage, bloodloss x5, unconscious 2 rounds, location destroyed -40 to applicable skills

 

Burn Critical (fire, electricity, acid)

-19 to -10  no extra damage

-9 to 0  no extra damage

0 to 10  no extra damage

11 to 20  no extra damage

21 to 30  no extra damage

31 to 40  +5 damage

41 to 50  +5 damage

51 to 60  +5 damage

61 to 70  +5 damage, location damaged -20 to applicable skills

71 to 80  +10 damage, location damaged -20 to applicable skills

81 to 90  +10 damage, location severely damaged -30 to applicable skills

91 to 100  +15 damage, location severely damaged -30 to applicable skills

101 to 110  +15 damage, location destroyed -40 to applicable skills

111 to 120  +20 damage, location destroyed -40 to applicable skills

Weapon Statistics

 

All weapons fall into one of the classes listed below. Most physical Powers (those that require touch) use the Hand-to-Hand skill to determine attack success. Hand-to-Hand damage is applied on a successful hit in addition to the damage done by the Power.

 

The Speed Factor is used in determining initiative - the higher the number, the better the chance of acting first in combat.

 

Weapon Class	Speed Factor	Damage
Hand to Hand	30	1d6+STR
Thrown weapons	25	Per weapon
Archery	15	1d10
Knife	25	1d10+STR
Sword	20	2d10+STR
Small Club	25	2d6+STR
Large Club	20	2d10+STR

 

 
 

 

Small Handgun  35  1d10+5

Large Handgun  20  2d10+5

Rifle   15  3d10

Assault Rifle  10  3d10 single

3d10+10 burst

3d10+20 full auto

Shotgun  15  3d10+5

Portable AT  0  5d10+30

Gunnery  5  5d10+30