Thief skills—especially those relating to sneaking and hiding—are one of the most commonly debated aspects of the game. The traditional Basic/Expert rules on which Old-School Essentials is based are somewhat lacking in detail in this area, requiring each referee to make their own rulings as to how thief skills are handled.
This article presents optional guidelines which may be used when adjudicating the skills of thieves (and related classes) and attempts by other characters to perform similar tasks.
Thieves gain a bonus to attack and damage rolls when attacking an unaware opponent from behind.
Surprise: A surprised opponent is considered unaware for one round. (See Encounters in Old-School Essentials.)
Hiding: An enemy who does not notice a hiding thief is considered unaware. See Hiding.
Sneaking: An enemy whom a thief who successfully sneaks up on is considered unaware. See Sneaking. Note that in the middle of combat, a roll to move silently is rarely required.
Other characters: Do not have the expertise to attempt this feat.
Thieves have the skill to climb sheer surfaces (i.e. vertical or very steep surfaces with only minimal handholds) without special equipment.
Easier circumstances: Thieves can climb non-sheer surfaces without a roll.
Other characters: May require a DEX check when climbing in a difficult or tense situation. Non-thieves cannot climb sheer surfaces without special equipment.
Thieves’ expertise with small, complex mechanisms allows them to find and remove treasure traps.
Room traps: Thieves have the standard 1-in-6 chance of finding room traps (see Searching under Dungeon Exploration in Old-School Essentials).
Other characters: Do not have the expertise to attempt this feat.
Descriptive handling of traps: PCs of all classes may try to find or remove traps of all kinds by describing their actions (e.g. poking a dagger in a lock, pouring water over a floor, etc.). In this way, it may be possible to find, bypass, or disable traps without a roll. The referee should adjudicate the effects of such actions based on the mechanisms of any traps present.
All characters can attempt to hear noises (see Doors under Dungeon Exploration in Old-School Essentials). Thieves’ chance of success increases with level.
Thieves have the skill to hide in shadows (i.e. when no other cover is available).
Easier circumstances: Thieves can hide behind decent cover without a roll.
Halflings and gnomes: Characters of these classes have a similar hiding ability to thieves which may be adjudicated using the same guidelines.
Other characters: May be required to roll (e.g. a DEX check or 2-in-6 chance) to successfully hide behind cover. Nonthieves have no chance of hiding if the only cover available is shadows.
Thieves’ expertise with maps and secret messages allows them (from 4th level) to read non-magical text in any language (including dead languages and basic codes).
Level of comprehension: The referee should decide how much of a text the thief comprehends. In the case of obscure languages, the thief may only understand the basic gist of a text, not the finer details.
Other characters: Do not have the expertise to attempt this feat.
Codes as puzzles: Adventures sometimes contain puzzles involving simple codes for players to unravel. The referee should decide whether to allow thieves’ read languages skill to aid in solving such puzzles.
Thieves have the skill to move silently (i.e. making absolutely no sound whatsoever).
Silent environments: Moving silently is required to sneak unnoticed in a completely silent environment. e.g. if a guard is standing quietly listening for intruders, a roll to move silently may be required.
Noisy environments: Thieves can sneak unnoticed without a roll in environments with background noise (i.e. where moving absolutely silently is unnecessary). This includes combat.
Failed rolls: A thief who fails their roll to move silently is still assumed to be moving quietly, thus the normal surprise rules apply (see notes below).
Other characters: When exploring (i.e. not in combat or fleeing), it is assumed that characters are attempting to move around quietly. In environments with some level of background noise, the surprise roll (see notes below) covers characters’ chance of sneaking unnoticed. Non-thieves cannot sneak unnoticed in silent environments.
Surprise: If PCs’ presence is not otherwise obvious (e.g. due to light sources or noisy actions), the standard surprise roll covers the chance of characters sneaking unnoticed in a non-silent environment. See Encounters in Old-School Essentials.
Thieves’ expertise with small, complex mechanisms allows them to pick locks.
Other characters: Do not have the expertise to attempt this feat.
Thieves are trained in the subtle art of picking pockets.
Other characters: Do not have the expertise to attempt this feat.