DERPS: Dozens’s Excellent Role-Playing System
it’s just TWERPS but slightly rewritten and clarified by me
2025-10-13
CONTENTS
ABOUT
What follows is more or less the verbatim text of TWERPS: The World’s Easiest Role-Playing System by Jeff and ’Manda Dee, 1987. I did just a little bit of reorganizing, and made a couple of tweaks and adjustments for clarity.
WELCOME
Welcome to DERPS, Dozens’s Excellent Role-Playing System.
To play, you will need:
- a Referee,
- at least one Player,
- some paper and pencils,
- and some 10-sided dice (d10).
Now go start playing.
CHARACTER CREATION
STRENGTH
Every DERPS character has a single attribute, and that is their Strength1. To determine a character’s beginning Strength, roll d10 and consult the table below.
| DIE ROLL | CHARACTER STRENGTH |
|---|---|
| 1 | 3 |
| 2-3 | 4 |
| 4-7 | 5 |
| 8-9 | 6 |
| 10 | 7 |
Naturally, the higher the Strength, the more powerful the character is, and the better they are at doing stuff.
THE COMBAT SYSTEM
TIME AND DISTANCE SCALE
The game is played on a hexagonal grid. 1 space represents a distance of 10 feet; one round of combat represents 10 seconds. To fight within melee range, the combatants must be together in the same hex. Up to four characters may be in a single hex at the same time. Only two allied characters may be in a single hex at one time.
MOVEMENT
Characters move in order of their current Strength scores, from lowest to highest. Each character can move up to as many spaces as they have Strength points at present. If a character runs, they may do nothing else in the turn, but they may move twice their normal movement (see Other Actions).
ORDER OF MOVEMENT AND ATTACK
When comparing current Strengths to find the order in which characters go, on a tie, player-characters always take priority. If multiple players are tied, or multiple NPCs, they may decide among themselves who goes first.
MOVEMENT RESTRICTIONS
A character must stop upon entering a hex containing a hostile opponent. When in such a hex, the character cannot leave unless they have scored a hit on their opponent in the previous round without being hit by him. If this is the case, the character may retreat 1 normal move at a cost of their action for the turn (see Other Actions).
During each round, a character may move once, and act once. A character with Strength 9 who acts on turn 9 but is wounded on turn 8 for 2 points (reducing their Strength to 7) does not get to go again on turn 7. However, wounds do apply if the character hasn’t gone yet; if the 9-point character is wounded for 2 points on turn 10, then their current Strength becomes 7, and they must now wait until turn 7 to act.
COMBAT
Characters attack in the order opposite of movement, from highest current Strength to lowest. To resolve an attack, the attacker and defender each roll a die and total their results with their current Strengths. If the attacker’s total exceeds the defender’s, then the attack hits and the defender takes damage (see Damage).
OTHER ACTIONS
Characters can do other things besides fighting, of course: picking pockets, manipulating machinery or items, casting spells, sneaking, running, etc. But they must do so in place of attacking in their turn.
Success in non-combat activities is covered under “How To Do Everything”.
DAMAGE
When a character takes damage, it reduces their current Strength. When current Strength is one (1), the character is rendered unconscious and will not wake up until the end of the fight, or until another character uses their turn to awaken him. When current Strength is zero (0), the character dies.
WEAPONS
Characters may use weapons in combat. Using a weapon may modify a character’s chances of hitting or allow more damage to be inflicted.
| Weapon | Plus to hit | Damage |
|---|---|---|
| Bare Hands | 0 | 1 |
| Dagger | 0 | 2 |
| Sword | 1 | 2 |
| Club | 1 | 1 |
| 2-hand Sword | 2 | 2 |
Missile Weapons are weapons that can strike from a distance.
| Weapon | Plus to Hit | Damage | Range (Hexes) |
|---|---|---|---|
| Rock | -1 | 1 | 3 |
| Dagger | 0 | 2 | 4 |
| Bow | 1 | 2 | 7 |
| Pistol | 0 | 2 | 5 |
| Rifle | 1 | 3 | 10 |
No missile weapon may be fired at an opponent in the attacker’s own
hex. There is a Range Modifier to missile attacks: range in hexes/3
(round down) is subtracted from the roll to hit. For example, firing a
bow 4 hexes is within its 7 hex range, and is possible. But it will
incur a 4/3 (-1, rounded down) Range Modifier. The final roll to hit
would be d10 + Strength - 1.
ARMOR
Armor protects characters from being hurt. Its value is added to the defensive roll during combat.
| Armor | Plus to defensive Strength |
|---|---|
| Leather | 1 |
| Chainmail | 2 |
| Plate Mail | 3 |
For example, if a character is wearing chainmail, they would roll
d10 + Strength + 2 to resist being hit in combat.
MULTIPLE CHARACTERS IN MELEE
An attacker may only engage one opponent at a time, and only that one opponent is subject to Movement Restrictions.
HEALING
After combat, any characters wo are still alive may restore their Strength scores to their original values.
HOW TO DO EVERYTHING
When characters try to do anything too difficult to be a sure thing, they must make a Saving Throw. A Saving Throw is just like a roll to hit, except that the defender is not another character, but rather a “Difficulty Level” from 1 to 10 set by the Referee2. If the character’s total beats the Difficulty total, then the character is successful.
| Difficulty | Target Number |
|---|---|
| Easy | 3 |
| Medium | 5 |
| Hard | 7 |
| Very Hard | 10 |
ADVENTURES
Players go on adventures. The Referee either makes it up on their own or uses a pre-packaged one.
NPCs are run by the Referee. They determine their identities, Strengths, and behavior. Random Strengths can be rolled on d10.
VICTORY AND ADVANCEMENT
After a battle, each surviving character on the winning side gets 1 Victory Point (VP). VPs can be traded in for a Strength increase. The cost for a Strength increase of +1 is the present Strength in VP. For example, to increase Strength from 6 to 7, a player must spend 6 VP.