Dungeon Adventuring (OSE SRD)

Sequence Per Turn

Check wandering monsters (every 2 turns, 1-in-6).
Party declares action.
Resolve and describe outcomes.
End-of-turn bookkeeping (torch burns, spells progress, hirelings age).

Detailed Procedure: Doors

Doors are the primary gateway mechanic in dungeon exploration. The door state determines interaction sequence.

Door States and Forced Entry

Stuck door (roll 1-in-6 if not obvious): - Try forcing: Strength check (save) + 1d6 damage to character on loud failure. - Loud: automatically triggers nearby wandering monster check. - Success: door opens normally thereafter.

Locked door: - Pick lock: Thief skill check (success chance per level). - Non-thief forced entry: as stuck door (strength save, 1d6 damage on failure, loud). - Alternately: find key, break lock (1d6 damage, loud). - Note: locked doors often have recent key usage (rust pattern, wear indicator).

Secret door: - Search from one side only (cannot search from both sides simultaneously). - Search roll: 1-in-6 base (disadvantage if actively being pursued). - Success: door revealed; character may now describe it. - Secret doors do NOT trap or lock unless explicitly mentioned. - Time cost: 1 turn per 10-foot wall section searched.

Listening at Doors

Procedure: - Party member places ear to door. - Listening check: 1-in-6 (Elves and Halflings may have advantage, per class). - Success: hear activity inside (or silence if room is empty). - Failure: hear nothing (room may still be occupied with quiet inhabitants). - Time cost: 1 round (approximately 10 minutes). - Limitation: cannot hear through thick stone or magically-silenced rooms.

Referee guidance: - Describe sounds if successful (breathing, movement, conversation, snoring, etc.). - Use silence as threat indicator (ambush predators, undead, magical guardians). - Allow repeat listening after 6+ turns if circumstances changed.

Movement and Exploration Rates

Movement rate fundamentally changes how long exploration takes and when fatigue/attrition matters.

Rate Modifiers Based on Situation

Exploring unknown territory (initial entry into dungeon or new area): - Base rate: per character class (Fighters, Thieves: standard rate; Magic-Users, Clerics: reduced rate if encumbered). - Actual ground covered: typically 120 feet per turn (6 seconds per foot). - Detail level: allow Party to search for secret doors, listen at doors, examine features.

Familiar territory (party has visited this area before): - Speed multiplier: ×3 of exploring rate (360 feet per turn). - Consequence: automatic failure for hidden door searches (party moving too fast). - Permission required: must explicitly state "we move cautiously and search" to revert to exploring rate.

Hazardous terrain (narrow passages, unstable floors, magical zones): - Reduced to half exploring rate; additional Save required to avoid damage. - Encumbrance penalty: characters carrying heavy armor/treasure suffer additional movement penalty (-10-20 feet per turn).

Torch and Light Duration

Torch duration: 6 turns (1 hour per torch).
Lantern with oil: 12 turns (2 hours per flask of oil).
Magical light: typically 12-24 turns or permanent until dispelled.
Out of light consequence: party blind (−4 penalty to all rolls, movement half rate).

Resting and Fatigue

Dungeon exploration is physically and psychologically taxing. Resting is mandatory to avoid mechanical penalties.

Resting Requirement

Mandatory rest frequency: 1 hour (6 turns) of every 8 hours (48 turns) in the dungeon.
Failure to rest: character gains Fatigue level.

Fatigue Accumulation and Penalties

Fatigue Level	Duration	Attack Roll	Damage Roll	Saving Throw	Movement	Other
None	—	Normal	Normal	Normal	Normal	—
1	After 6 missed hours	−1	−1	−1	Normal	Can cast spells normally
2	After 12 missed hours	−2	−2	−2	−5 feet/turn	Spell slots reduced by half
3	After 18 missed hours	−3	−3	−3	−10 feet/turn	Spell slots reduced to zero (can't cast)
4+	After 24+ missed hours	Character collapses and cannot act	—	—	—	May die without healing

Rest recovery: 1 hour of rest removes 1 Fatigue level. Full recovery (Fatigue 0) requires 8 hours and exit from dungeon OR magical healing.

Note: Resting in dungeon is risky; wandering monster checks still occur during rest periods.

Searching and Trap Detection

Searching is the proactive method for finding hidden features or detecting traps before triggering them.

Secret Door Search (Already Under Doors)

See above; 1-in-6 per 10-foot section per turn of searching.

Room Trap Search

Procedure: - Character declares they are searching for traps in the room. - Search roll: 1-in-6 (Thieves may add class bonus). - Success: character detects trap present and general location (e.g., "wire across floor near west wall"). - Failure: character does not detect trap; may still trigger it if moving carelessly. - Time cost: 1 turn per room.

Trap trigger mechanism: - Trap activation check: 2-in-6 when relevant action occurs (stepping on pressure plate, opening treasure chest, etc.). - Success (rolls 1-2): trap activates; characters make Save to avoid full damage (or half damage on save, per trap design). - Failure (rolls 3-6): trap does not activate; trigger degrades or misfires.

Treasure Trap Search

Applies when character interacts with locked chest, jeweled idol, or similar high-value item.

Procedure: - Character searches item before opening/moving. - Trap trigger: 2-in-6 baseline. - Advanced search (Thief with high level or magic-user with Detect Magic): improves odds to 1-in-6 chance of trap trigger. - Without searching: flat 2-in-6 trigger chance on opening/moving.

Common treasure traps: - Poison gas (Save or die / Save for half damage). - Dart spray (1d6 damage per dart, multiple darts possible). - Blade trap (2d6 damage, triggered on opening). - Curse (magical, usually curse or Lawful Retribution).

Wandering Monsters and Encounter Cadence

Wandering monsters represent living threats patrolling or opportunistically hunting in the dungeon.

Wandering Monster Check Frequency

Standard frequency: every 2 turns.
Adjustments:
If party is loud (forced door, combat, spell effects): check each turn.
If party is being actively hunted (after combat, after alarm raised): check each turn.
If party moves cautiously and quietly (no light source, Stealth class advantage): check every 3 turns.

Wandering Monster Encounter Odds

Base encounter chance: 1-in-6 on each check.
Improvements (GM override for pacing):
1-in-4 if many encounters have been avoided (to ramp up pressure).
1-in-8 if encounters have been frequent (to allow recovery).
1-in-12 in lower dungeon levels (deeper = fewer wanderers, more specialized guardians).

Encounter Resolution

Random determination: roll 1d6. On 1, wandering monster appears.
Distance: 2d6×10 feet away initially; roll for surprise (same as normal combat).
Reaction: roll reaction table (typically 2d6) to determine monster behavior.
Combat or negotiation: proceed based on reaction.

Lair Integration

Monsters with declared lair: - Wandering monsters may be out-of-lair (hunting, patrolling). - In-lair encounters should be more structured (trap-prepared, advantage given to inhabitants). - Lair note in monster entry clarifies if wandering check is for OUT-of-lair or patrol pattern.

Trap Mechanics Summary

Trigger Probability

Trap Type	Baseline Trigger	Searched	Advanced Search
Room trap (routine)	2-in-6	Not detected	1-in-6
Treasure trap	2-in-6	Detected, 1-in-6 trigger	Detected, no trigger
Magical curse trap	Special	Detect Magic required	Cleanse/Neutralize

Damage Resolution

Trap damage type: varies (physical, magical, environmental).
Saving throw: most traps allow one Save (attack roll vs. AC-equivalent for physical traps, magical Save for curse/poison).
Half damage on success: standard.
Full damage on failure: character takes full effect (death or major status effect possible).

Disarming Traps

Non-magical trap (Thief ability or extraordinary roll): - Thief level check; success disarms trap completely. - Non-thief attempting disarm: automatic failure + immediate trigger (2-in-6 applies).

Magical trap (curse, glyph, magical pressure): - Requires Dispel Magic, Neutralize Poison, or equivalent spell. - Alternative: Pay the cost (fail Save and accept effect, then trap is "spent").

Hearing, Watching, and Environmental Cues

Dungeon features often telegraph danger or presence:

Listen for movement (separate from door listening): automatic if party is quiet; 1-in-4 chance to hear distant noise (approaching monsters, water flows, etc.).
Watch for light (torchlight reflection in polished metal, phosphorescent moss, magical auras): automatic at 60+ feet if moving toward light source.
Smell distinctive odors (sulfur, decay, perfume): automatic in same room.
Feel air movement (breeze from hidden passage, warm air from forge): GM discretion; often foreshadows secret door or large chamber nearby.

Procedure Variations for Minimal B/X

For classless systems or other minimal B/X frameworks, simplify:

Single movement rate (120 feet per turn exploring, 360 feet familiar).
Fatigue threshold: every 8 turns requires 1 turn rest (no level progression on fatigue).
Combined search roll: 1-in-6 for any hidden feature (trap, secret door, treasure).
Wandering cadence: every 3 turns (1-in-6).

These modifications maintain exploration tension without class-specific mechanics.