RPG Horizon

The Hidden Skills In Basic Dungeons & Dragons

The OSR community often debates skill systems, with some members opposing them completely, others preferring simplicity, and many agreeing that skill systems in 3rd edition and later editions have too much complexity. It seems that each new Old School D&D inspired game has its own skill system added to it. When discussing skill systems in B/X, some readers might be thinking of the ability check system presented in Old-School Essentials.

Ability Checks

The referee may use a character’s ability scores to determine the character’s chance of succeeding at various challenging tasks.

Rolling an ability check: The player rolls 1d20 and, if the result is less than or equal to the ability, the check succeeds. If the roll is greater than the ability, the check fails.

Modifiers: Bonuses or penalties to the roll may be applied, depending on the difficulty of the task. A modifier of –4 would be a relatively easy ability check, and a +4 would be very difficult.

1s and 20s: An unmodified roll of 1 should be treated as a success and a 20 treated as a failure.

The skill system being discussed is not this ability check system, which may be more familiar to modern D&D players. Rather, the skill system can be found elsewhere, and that is the focus of today's discussion. The first place we see it is when discussing dungeon adventuring.


Open doors: The chance of success with attempts to force open a stuck door.

Skills can range from a 1-in-6 chance to a 5-in-6 chance, and are commonly found in various places. These skills are generally common to all adventurers, although there are some exceptions that will be mentioned later. The force open door skill above scales with an adventurers strength.

While all common skills are given as a X-in-6 chance, some abilities are given using this chance that behave more like a class specific skill. These should in an ideal world have been rewritten as a percentille chance. In this article these cases will be termed 'thief skills', due to their similarities with the thief specific rules.

Listening at Doors

Chance of success: PCs have a 1-in-6 chance of detecting subtle sounds beyond a door. (Some types of adventurers may have an increased chance of success.)

The listening at doors skill that is improved for demi-humans, but this is another skill common to all adventurers.


Chance of success: If a character is searching in the right location, there is a base 1-in-6 chance of finding a secret door or room trap. (Some types of adventurers may have an increased chance.)

The search skill has improvements for demi-humans but is otherwise a skill common to all adventurers.


Chance of triggering: Every time a character makes an action that could trigger a trap, there is a 2-in-6 chance of the trap being sprung.

Another skill common to all adventurers is the ability to avoid traps, which can be thought of as a luck skill. This skill has a 4-in-6 chance of success. However, it is less clear how this skill applies in certain cases. Some triggering mechanisms may have a 100% chance of activating (such as pulling a lever).


Foraging for herbs, fruits, nuts, etc. can be performed alongside normal movement (see Overland Travel). The party has a 1-in-6 chance per day of finding enough food for 1d6 human-sized beings.

The forage skill is interesting because it is a "whole party skill" rather than an individual skill. More information about why this distinction will be provided later.


Hunting must be engaged in as the sole activity for a day—no travelling or resting is possible. When hunting, there is a 1-in-6 chance of encountering animals which may be suitable for eating (if they can be caught!). This is in addition to the normal chance of random encounters (see Wandering Monsters).

The hunt skill works the same as Foraging, but takes up far more of the day.

Losing Direction

At the start of each day of travel, the referee should roll to determine if the group loses direction. The probability depends on the terrain being traversed:

  • Clear, grasslands: 1-in-6.
  • Barren lands, hills, mountains, woods: 2-in-6.
  • Desert, jungle, swamp: 3-in-6.

The pathfinding skill allows a party to navigate through various types of terrain, with the difficulty represented by a chance of success ranging from 3-in-6 to 3-in-5. Navigating while waterborne has a 4-in-6 chance of success, but using paths and rivers eliminates the need for this skill. However, it should be noted that navigating while on water requires the assistance of a specific navigator, and thus not all adventurers have this skill.


Forceful boarding: If the occupants of one vehicle wish to forcefully board the other vehicle, there is a 2-in-6 chance of being able to successfully manoeuvre the vehicle into a boarding position. The two vehicles may then be clamped together with grappling hooks.

The boarding skill is less general, but it is present.

Surprise Checks

Each side that is not already aware of the other’s presence rolls 1d6.

Monsters: The referee rolls for monsters.

PCs: One player rolls for the adventuring party as a whole.

Results: A result of 1 or 2 means the side is surprised.

The final universal skill is hidden in the rules for "surprise", and is a 2-in-6 stealth skill. By changing the perspective from "one side being surprised" to "the other side being surprising" this becomes more clear. This is not strictly equivalent, as interpretations will change when dealing with more than two sides, but it is useful to think about for the purposes of the skills discussion.

There are also skills listed in the classic fantasy genre rules, which link to specific equipment and classes instead of to core rules.

Tinder box: Used to light fires, including torches. Using a tinder box takes one round. There is a 2-in-6 chance of success per round.

This can be treated as a common start a fire skill.


Detect Construction Tricks

As expert miners, dwarves have a 2-in-6 chance of being able to detect new construction, sliding walls, or sloping passages when searching.

Detect Room Traps

Due to their expertise with construction, dwarves have a 2-in-6 chance of detecting non-magical room traps when search-ing (see Dungeon Adventuring in Core Rules).

Listening at Doors

Dwarves have a 2-in-6 chance of hearing noises (see Dungeon Adventuring in Core Rules).


Detect Secret Doors

Elves have keen eyes that allow them, when actively searching, to detect hidden and secret doors with a 2-in-6 chance (see Dungeon Adventuring in Core Rules).

Listening at Doors

Elves have a 2-in-6 chance of hearing noises (see Dungeon Adventuring in Core Rules).

The demihumans have improved search and listen skills in certain contexts.



In dungeons, a halfling can hide in shadows or behind other forms of cover. The chance of success is 2-in-6. Hiding requires the halfling to be motionless.

Listening at Doors

Halflings have a 2-in-6 chance of hearing noises (see Dungeon Adventuring in Core Rules).

From the surprise rules, all adventurers have a common 2-in-6 chance to be stealthy. This is the same as the halflings, however they have an additional level of stealth when hiding in dungeons. This isn't a common or shared skill, and so should be thought of more as a 33% thief skill than a 2-in-6. Like the thief, this allows for situations where the halfling is hidden but the rest of the party is not.

Halflings also have an improved listen skill, but not an improved search skill.


Thief Skills

▶ Hear noise (HN): In a quiet environ-ment (e.g. not in combat), a thief may attempt to listen at a door or to hear the sounds of something (e.g. a wandering monster) approaching.

The thief has an improved listen skill, similar to the demi-humans, but it is one that improves as the thief gains experience.

Moving away from pure B/X for completeness here are the skills from the OSE Advanced Fantasy Genre Rules.


Foraging and Hunting

A party with a barbarian succeeds at foraging with a 2-in-6 chance and finds prey when hunting with a 5-in-6 chance (see Wilderness Adventuring in Core Rules).

As we saw with stealth earlier, some checks are made for the whole group, not an individual adventurer. These can be improved by a specific class, and that improvement applies to the entire group. For the forage and hunt skills, the Barbarian improves them for the entire party. This also opens design space for a class or ability that improves the entire parties stealth.



From 2nd level, a bard has a 2-in-6 chance of knowing lore pertaining to monsters, magic items, or heroes of folk-tale or legend. This ability may be used to identify the nature and powers of magic items.

Though presented as a 2-in-6 skill, the Bard's lore ability is more like a thief skill, and so should perhaps be stated as a 33% chance instead. Alternatively, you could treat lore as a common skill and give all other classes 1-in-6.

All of the demi-human classes have search and listen improvements as in the classic fantasy rules.



A party with a druid has only a 1-in-6 chance of getting lost in woodlands. See Wilderness Adventuring in Core Rules.

Druids have an improved 5-in-6 pathfinding skill in the wilderness, improving the entire groups navigation as the Barbarian did to forage and hunt.



Underground, duergars have a 3-in-6 chance of moving silently.

The ability to move silently underground is being presented as a common skill, but it is actually a thief skill. Duergar have a 50% chance of doing so. However, this could be changed (as suggested with Bard lore) so that all adventurers have a certain chance to move silently, regardless of their class.

Gnomes have the same 2-in-6 small person bonus to hiding as halflings.


Foraging and Hunting

A party with a ranger succeeds at foraging with a 2-in-6 chance and finds prey when hunting with a 5-in-6 chance (see Wilderness Adventuring in Core Rules

Surprise Attack

In the wilderness, a ranger has a 3-in-6 chance of going unnoticed when sneaking up on a target. If the ranger goes unnoticed, the target may be surprised (see Surprise under Encounters in Core Rules)

The Ranger has the same improvement to the forage and hunt group skills as the Barbarian. Additionally, the ranger has an improvement to stealth. This is worded as a 3-in-6 skill, but as it only applies to the ranger is more similar to a 50% hide in wilderness skill.


Blend into Stone

Svirfneblins have the uncanny ability to go unnoticed when in an environment of natural or carved stone so long as they remain silent and motionless. The chance of success is 4-in-6 in gloomy conditions or 2-in-6 in well-lit conditions.

Stone Murmurs

Svirfneblins can understand the imper-ceptible grumblings of stone. If a svirf-neblin stands quietly for one turn with their ear pressed against a stone surface, they have a 2-in-6 chance of divining one of the following pieces of information (player’s choice):

  • The presence of secret doors in the stone, within 10’.
  • The presence of gems or precious met-als, up to 30’ beyond the surface.
  • The presence of living creatures, up to 30’ beyond the surface.
  • The presence of bodies of water or open spaces, up to 60’ beyond the surface.

The Svirneblin also has a stealth improvement worded as a common skill. These may be treated as a 66% and 33% thief skill for hide in gloomy stone and hide in well-lit stone.

The stone murmers ability is also not a common skill, and so can be treated as a 33% thief skill.

This concludes a summary of all of the X-in-6 universal skills that underpin B/X D&D.

Individual Skills

Inidividual skills are rolled for every person attempting an activity.

Group Skills

Group skills are performed by the entire group, with a single character leading the activity who can provide their experience as a bonus to everyone.

Author: Lucille L. Blumire

Published: Sat, 11 Jul 2020 17:04:00 GMT

Original: The skills you didn't know you had. Old school musings on the B/X skill system.