AN INTRODUCTION TO DUNGEON CRAWLING

You want to run a “Dungeon Crawl” adventure… Not just an adventure in a "dungeon", but a Dungeon Crawl - that distinct, classic mode of RPG play about exploring a fantastical space, obtaining its treasures, and unraveling its secrets ... while surviving its dangers. Notably, the first rule of Dungeon Crawls is that surviving dangers does not always mean destroying or even overcoming them.

Dungeon Crawls should emphasize the tense experience of exploring a wondrous and dangerous location. These adventures will be more enjoyable if the referee pays attention to and uses the full suite of exploration rules while omitting even traditional rules that limit them, such as “darkvision” or “infravision” as a natural ability for characters. I encourage you to play with turnkeeping, encumbrance, and random encounters so you can experience how these mechanics work together to make navigating the fictional space tense. To help, this essay offers advice and even some streamlined alternatives to some classic exploration mechanics.

However, beyond mere game mechanics, this style of RPG depends upon utilizing a set of procedures—rules about how, when, and in what order the characters can act—that should make navigating the unexplored depths meaningfully tense. In particular the classic version of Dungeon Crawling relies on three ideas, and their corresponding rules, without some version of which the adventure is likely to be a less enjoyable experience.

1) Turn Keeping: Turns are important! They are the foundation on which all other Dungeon Crawl procedures are built. Though the Exploration Turn or just “Turn” is commonly described as ‘about ten minutes of time within the game world,’ it’s best not to get hung up on exact measures of time. This is a game, and like many games it is organized by turns. One player goes, then the next—or in this case: the player group goes, then the environment reacts through the referee. Because of this it’s more useful to think of Exploration Turns as an abstract unit representing the amount of in-game time it takes to perform most useful actions: moving, examining a room, or interacting with some object. After the players act, the setting acts and takes its own ‘turn’ by depleting the party’s supplies and checking for a random encounter. Of course some useful actions may require multiple Turns, and that creates greater risk.

2) Limited Supplies: Attrition is one way a Dungeon resists being explored. Players are rewarded for learning a Dungeon’s secrets by being able to venture further while enduring less attrition. Hence encumbrance rules (either based on coin (CN) weight or a “slot” system) are an essential limitation on the player’s resources. Time spent in the dungeon expends resources, especially light, and players must retreat before being trapped in deadly darkness. Encumbrance and supplies also force players to make decisions about what treasure to take. 

3) Randomized Risk: Dungeons are filled with tricks, traps, foes, puzzles, and confusing passages. The safest way to deal with them is to slowly and cautiously move through the space checking everything with the infamous  10’ pole and other tools. This makes for a tedious evening of adventure gaming. Besides the depletion of light and other supplies, the counterweight to player caution is randomized risk. Random Encounters are rolled once per Turn or two, and threaten the party with a potentially hostile creature that offers no or very limited rewards for fighting because most or all character advancement comes through recovering treasure. Worse, Random Encounters will often be more powerful than the party, as it is not essential to fight them and they represent the manifestation of risk for players who push their luck too far.

Together these three design principles and their supporting mechanics create the tripod that holds up a Dungeon Crawl. Though some may seem silly in the abstract, without them exploration becomes far less exciting and tense.

DELVING DEEPER INTO DUNGEON CRAWLING
A Dungeon Crawl is what exactly? Dungeon Crawls proper are a distinct mode of RPG play. They may be one of the oldest modes, but they are not a baseline that all styles of play easily refer back to. Running a Dungeon Crawl is not intuitive, and lessons learned from other styles of play may contradict its needs. This makes it essential to approach this mode of play on its own terms. Stated simply, a Dungeon Crawl is “a game of exploration in a fantastic space”.

By game I mean that it will have rules and structure. By exploration I mean that discovery is both the reward for, and the key tool of skillful play. Finally, by space I mean that the relationships between important elements are governed by distance and direction. Play proceeds room by room, and players must choose where to go next and by what route. As referee, facilitating this mode of play requires either an intimate familiarity with exploring ancient ruins…or a set of helpful rules.

Here I describe both the general ideas of Dungeon Crawling, and the rules I personally use to facilitate dungeon crawling play. They are modular. I encourage you to take what you are comfortable with, and ignore the rest. The rules provided by OSE and similar systems are perfectly serviceable, but I’ve found that they require more of my attention and mental energy than I am willing to spend. I’ve also found that they are designed with lengthy in-person sessions in mind. Sensibly so, given when the source material was originally written, but I haven’t had the opportunity to play that way very often in the past decade—especially since 2020!

On to fundamentals and simplifications... Rules for exploration exist to make navigation exciting. The three elements mentioned above are the genre’s fundamentals, and work in concert focus the game on exploration: Turn Keeping, Limited Supplies, and Random Risk. To keep these active in the game there are both mechanics (rules to determine what happens in the game) and procedures (rules about how and when to apply mechanics). 

Turn Keeping sets character actions within a framework that creates a cost for player decisions. If decisions have no cost, or if the cost is too low, exploration easily gets bogged down as the players take every precaution they can imagine. This also encourages the referee to play a game of ‘gotcha,’ punishing lapses and oversights, because player mistakes are the only source of risk. By transparently tracking character actions across Exploration Turns, and in combination with the dual pressures of Limited Supplies and Randomized Risk, Turn Keeping gives the setting a chance to respond to player decisions … It allows risk. That each player action has a clear cost and risk associated with it discourages excessive caution. This also frees the referee from needing to outthink the players with perfect obstacles to create challenge, and allows them to offer more benefit of the doubt when interpreting player actions.

The Exploration Turn is traditionally said to be “10 minutes”, but I prefer to abstract time. In the dangerous dark, without clocks, under stress, senses muddled by greed, adrenaline, and ancient sorcery, counting the minutes is beyond the characters’ abilities. Rather, my Turns are like those in a board or card game. A Turn is the amount of time it takes to perform some significant action, a player “move”: searching an area, picking a lock, interacting with a strange device, smashing down a door, or conversing with an NPC. Additional granular detail isn’t necessary.

Moving from one area to another is also a Turn-length action, which saves everyone the trouble of counting squares on a map. Particularly long hallways or huge rooms may take more than one Turn to traverse, and encumbered characters will take two Turns to move a distance that normally requires one. Specific movement rates and distances can be reserved for combat.

Limited Supplies  limit the tools players may bring into the dungeon, and the treasure they can carry out. It spurs them to less cautious action by its constant ‘ticking down’ of resources—primarily light. Being trapped in the dark away from any known exit is certain doom (see LOST IN THE DARK below). The classic problem with supply is that characters are either able to carry so much that it doesn’t matter, or the method used to track it is so annoying that the effort is discarded altogether. 

I eschew the complex “coin” based weight system used by OSE in favor of Slot Encumbrance. Each character is allowed a number of slots equal to 6 + ½ their Strength score, meaning each character can hold between seven and fifteen “significant items” before becoming encumbered. Significant items are things like armor (it all “weighs” the same), a weapon, a quiver or box of ammunition, a bundle of three torches, a lantern, a flask of oil, a potion, a rope and grapple, a kit of specialist’s (like thieves) tools, or any other item that’s not inconsequential in either size or importance. Items such as clothing, a canteen, a piece of chalk, jewelry or gems can all be carried for free. Slot encumbrance works well because it is clear, easy to track, and limited enough to make supplies matter in even fairly short sessions.

A useful side effect of supply tracking is that players will want to escape the dungeon at the end of each session to restock. This makes a shifting cast of adventurers easier to manage. It also encourages the hiring of hench people, who increase the party’s ability to carry things, but are prone to flee on a failed morale check. Finally, supply offers another resource besides Hit Points and spells that players can expend to overcome obstacles. A referee should both encourage this kind of expenditure (such as using gold or rations to distract enemies), and leverage it as a consequence for failed or foolish actions. Even creatures and traps in the dungeon may attack supplies and equipment (such as the famous rust monster).

COINS AND HEAVY TREASURES Referees sometimes worry that Slot Encumbrance will make the weight of recovered coins more difficult to manage. First, use fewer coin hoards as treasure … but to address the issue: I allow each PC one free “purse” of up to 1,000 coins, with each additional thousand (or portion of a thousand) taking up one slot. This assumes coins are far less than the “CN weight” of 1.6 oz each … which ancient coins usually were: Roman golden solidus and silver denarius were rarely more than a quarter of an oz. When writing or using an adventure for publication, treasure with a listed coin weight (cn) requires a slot to carry, while those without (jewelry mostly) don’t. Some items of treasure may be so heavy or bulky that they require multiple slots, multiple party members, or simply automatically encumber anyone who picks them up.

Randomized Risk goads the players to boldness by attaching an unknown cost to each Exploration Turn they spend. While the constant ticking down of supply sets a calculable limit on how long a delve can last, randomized risk—primarily the Random Encounter—is a pressure that cannot easily be quantified. In games where combat is dangerous, healing limited, and XP primarily (or only) received for recovering treasure, encounters exist almost purely as a threat. Since they are random, yet certain to occur eventually, players are prodded to move quickly, take risks, and when no encounters occur to press their luck by delving deeper. 

Dungeon exploration has always included a periodic die roll for encounters, which makes it a convenient mechanic to attach other considerations to. This innovation, the Hazard Die, is rolled at the start of each Turn. The results I typically use are:

	A 1D6 HAZARD DIE SYSTEM
1.	Encounter — treat as standard.
2.	Omen — an ominous portent of the next encounter. In dangerous locations, if omen is rolled again without an intervening encounter, treat the omen as an encounter. In safer locations treat every other encounter rolled as an omen.
3.	Torches burn down — the party’s torches are guttering and about to go out. If they have replacements they may be lit without penalty.
4.	Other lights burn down — lanterns burn through half a flask of oil. Other non-magical sources, such as candles, go out.
5.	Spell depletion — magical effects, such as potions and spells, wear off. Those with short durations (1 Turn or less) do not use this mechanic. Effects which last longer than 6 Turns may be given a “pip” for each 6, one of which is lost each time this is rolled. Effects with listed durations of a day or longer can be considered to last for the rest of the session.
6.	Exhaustion — the party gains 1 pip of exhaustion as the stresses of dungeon exploration take their toll. At any time, so long as they have water or rations, they can choose to spend a Turn resting and reset their exhaustion to zero. If the party ever has 3 pips of exhaustion then all members are treated as Encumbered, with a -2 to all rolls, until they rest.

These results are not absolute. The referee may wish to use the Hazard Die to track local effects such as hauntings or earthquakes. Many games reserve 6 as a “free” result, or for “NPC chatter.” To make room for these additions, lights burning down can also be combined together, or even added to spell depletion. Additionally, some groups enjoy the danger of multiple events occurring simultaneously and roll two differently colored dice each Turn. One die is the Hazard Die, and if the other ever rolls doubles with it, a second Hazard die is rolled for the same Turn.

The Hazard Die supplements the other mechanical changes suggested here. It adds a rhythmic “punctuation” to Turn Keeping, which helps clarify the advancement of game time. It replaces much of the tedious bookkeeping involved in Supply Tracking. I have played for a dozen years with these mechanics and to some degree has been designed to facilitate them (though I make sure my work is also playtested without them). More specifically, I try to design to facilitate short sessions (under 5 hours) where the party returns to the surface at the end of each one, and simplifications like the Hazard Die help with short sessions. 

I must note that none of these suggestions are entirely original. They were refined through many games, blog posts, and discussions during the 2010 - 2016 period of the Old School Renaissance. In particular, the Hazard Die (both its name and its adoption) must be credited to the Necropraxis blog. More on its development and other interesting design ideas can be found there and in the publication “Wonder & Wickedness.” 

GAMIFICATION I’ve heard frequent complaints that the Hazard Die makes play feel less immersive, that it is “unrealistic.” I made the same arguments when I was first exposed to the mechanic, but I don’t find them especially compelling now. RPGs are filled with abstraction, simplification, and gamified mechanics. One could not play otherwise. Though this mechanic might be unfamiliar, it doesn’t change the structure of play significantly. After using the Hazard Die for several years I’ve concluded that it dramatically reduces the record keeping burden on the referee, adds tension to supply tracking, and contributes greatly to making exploration exciting. And if occasionally a torch burns out a single Turn after it was lit, then perhaps the party was swindled with inferior goods, or perhaps this dungeon is offended by the interruption to its darkness.

LOST IN THE DARK

When light sources are limited, the referee must be prepared to adjudicate what happens if the lights run out. Playing out Turns of the party navigating by touch is possible, but time consuming and usually unpleasant. Instead, consider a single roll that simplifies the risk and saves time—useful, given that supply usually runs out toward the end of a session when everyone is ready to wrap things up. These penalties are harsh, but running out of light in a dungeon is a serious failure. The alternative is fading to black and proclaiming that the party are all lost forever in the dark beneath the earth. These same mechanics can apply if the party makes the poor decision to camp in the dungeon. Though a good referee will warn them that doing so outside a place of safety. It’s up to each referee to decide if anywhere within a dungeon offers such a refuge.

If lost without light, each PC rolls a 4D6 minus Wisdom, and refers to the table below. Optionally, the referee may add 1 to the result for each level beneath the surface the party was when they lost their light.

LOST IN THE UNCANNY DARKNESS - ROLL 4D6 MINUS WISDOM
0 or Less.	UNSCATHED!
1.	DISORIENTED. The adventurer makes it out with only minor injuries and traumas. They begin the next session with -1 HP per HD, and suffer a -1 to their attack rolls.
2.	IMPOVERISHED. The character is shaken but unharmed. They dropped all the treasure they were carrying in their escape, which has been claimed by a denizen of the dungeon.
3.	BATTERED. The escapee is marked by mysterious cuts, strange bite marks, and a frayed psyche. They begin next session with ½ their normal HP.
4.	MANGLED. The adventurer makes it to the surface gravely wounded. They begin next session with ⅓ their normal HP, and must Save vs. Paralysis or permanently lose 1 CON.
5.	NAKED & AFRAID. The character stumbles into the light stripped of all equipment and treasure, but uninjured. The horrors of the dark are stamped on them. They permanently lose 1 WIS.
6.	LOST. The adventurer is left wandering in the dark. For the next two sessions they replace the 6th result on each level’s Random Encounters table. If found they will be malnourished, and will have lost all their equipment and treasure beyond 5 items of the player’s choosing. If not found within two sessions, treat the character as RISEN (see below).
7.	DURANCE. One of the dungeon’s factions takes the character hostage seeking advantage. If the party makes no bargain for their release within two sessions the character may be eaten, killed, or turned to the faction’s cause. If being held hostage is not possible, treat this result as LOST.
8.	MAIMED. The escapee is discovered a few days later. They made it to the dungeon’s exit, but are nearly dead from a permanently damaging wound. They lose 1D6/2 points from a randomly determined ability score, representing an appropriate trauma. (INT loss may suggest concussion, DEX loss could be cut ligaments or missing fingers, etc). All the character’s equipment and treasure are also destroyed, or lost within the dungeon.
9.	POSSESSED. Something took hold of the lost adventurer in the darkness. Now they prowl the corridors for flesh and gold, or have allied themselves to one of the dungeon’s factions. If subdued and captured within a few sessions they might be returned to their old self by casting Remove Curse, or by some other magical means.
10.	SLAIN. Perhaps cut down by robbers, rotting at the bottom of a pit, or eaten by a grue. The body might be discovered, but likely will have been looted.
11.	GONE. No trace of the lost adventurer or their equipment can be discovered.
12 plus.	RISEN. The lost adventurer roams the dungeon as a vengeful undead horror, hunting the party with a great hatred for those who survived. They have either the same HD and abilities as the original PC, or have become a Wight (whichever is stronger).

A version of this essay will be included in an Appendix to my upcoming “Bones of Bronze”, which is finishing layout but still needs more art (meaning I have to draw a lot of skeletons) and additional editing  but hopefully will be ready in summer 2025. It’s over 200 pages of Crystal Frontier dungeon crawling, but this time tomb robbers are drawn into the ancient mysteries of the frontier, exploring a five level bronze age barrow full of various factions and secrets that reveal information about the regions history to those that wish to investigate.  The adventure is densely keyed and contains many piece of supporting information and optional content, beyond brief notes and this essay to help novice referees.  Appendices and other supplementary details include player ready maps for use with VTT’s, referee aides for puzzles and faction management, details on several power ancient tomb blades and numerous magic items, a spellbook based tool for introducing necromancy as a Magic User subclass, a bestiary, and Truvidas Grape - a naive scholar who may hire the party to escort him through the barrow while he researches his pet theories on antediluvian blood magic.