Tag Archives: d20

How to Turn D&D’s Swingy d20 Checks Into a Feature That Can Improve Your Game

Dungeons & Dragons uses d20 rolls to randomly determine success and failure. A single d20 yields extreme numbers like 1 and 20 as frequently as middle numbers, and this shapes the game. In the real world, experts attempting routine tasks rarely fail and novices making a first try rarely succeed. But D&D tests rolled on a d20 often lead experts to botch checks and the untrained and untalented to luck into success. The d20 often makes experts look inept, defying everyday experience.

Seeking a better match with reality, some roleplaying game designers create games with core mechanics that total the results of multiple dice. This creates a bell-shaped curve of probabilities that makes the highest and lowest numbers rare, and lets players build heroes that show the sort of reliable competence we see in fiction.

Meanwhile, in D&D worlds, the mighty barbarian fails to open a pickle jar, and then hands it to the pencil-necked wizard who easily opens the lid. Such outcomes feel wrong, but with the right mindset, that swingy d20 can become a storytelling feature rather than a bug.

To start, as a DM, don’t ask the barbarian for a check to open the damn jar. “Remember that dice don’t run your game—you do,” explains the Dungeon Master’s Guide. “At any time, you can decide that a player’s action is automatically successful.” This means skipping rolls on tasks “so easy and so free of conflict and stress that there should be no chance of failure.” For best results, rate “easy” generously. Let talented or skilled characters skip the rolls where only a comical fumble would explain failure.

For knowledge and information checks, drop the roll and tell players what their characters should know. I often reveal lore based on characters’ proficiencies and background. For instance, the druid knows of the cursed trees surrounding the grove, while the dwarf knows about the flooded mine. This technique works especially well for the information players must learn to continue. Essential backstory feels like a reward for a character’s choices. Players won’t know what knowledge comes from their characters’ aptitude and what you had to reveal to advance the plot.

If everyone at the table rolls a check with the swingy d20, someone usually rolls high. In D&D, letting everyone roll certain checks practically guarantees success. The one wizard proficient in, say, the Arcana skill will seldom roll a better success than every one of the other 4 know-nothings in the party.

For a real test that acknowledges the skilled and talented characters, allow fewer characters to roll. Limit the check to characters with proficiency. This rewards the cleric proficient in religion even if their knowledge is hampered by low Intelligence.

Granting an expert character advantage reduces the chance of an unlikely fumble, and improves the chance that talent will lead to success.

  • Limit a check to the active character, possibly just the person who asked, and then grant advantage based on the party’s advice and assistance. This encourages groups to have the character most suited to a challenge to lead the way.
  • Limit a check to the skilled characters and then grant advantage based on the party’s help. I love when this enables a quiet player to gain the spotlight based on their character’s aptitude.

When someone fumbles a roll, instead of describing the failure in a way that makes the hero or monster seem inept or comical, describe the stumble so the fault comes from tough opposition or an impossible situation. DMs feel tempted to narrate bad rolls for laughs. We can narrate a 1 with a description of how someone’s hat tilted to cover their eyes and gain an easy laugh that feels fun in the moment. But too many descriptions like that turn characters into clowns and their opponents into jokes. Instead, use a 1 to describe a foe’s superhuman speed or the swirling hot ash clogging the air and stinging the heroes’ eyes. When you describe outcomes, even the fumbles, flatter your heroes and monsters.

Despite all these techniques, the d20 brings extreme numbers that create shocking failures and inexplicable successes. To cope, treat the swings as a storytelling challenge to embrace. The dice make us surrender some control, adding the risk that the story won’t go as we plan. Events beyond our control make the game unpredictable and exciting. Savor that.

“As often as possible, I like to stick with whatever the dice tell me, partly because as a DM I love to be surprised,” explains D&D lead rules designer Jeremy Crawford. “I love that sense whenever I sit down at any table where I’m DMing. I don’t actually know what’s going to happen because I don’t know what the dice are going to say. The dice can turn something I thought was going to be a cakewalk into a life or death struggle.”

The dice nudge, and sometimes shove, D&D games out of their expected course. They give D&D games a way to surprise us, and to challenge us to become more creative—to invent storytelling twists we would not have imagined without the random nudge.

Why D&D’s d20 Tests Make Experts Look Inept and How to Make the Best of It

Decades ago, I read game designer Steve Jackson explain why he swapped the d20 to-hit roll in Dungeons & Dragons for the 3d6 roll used in his alternative combat system Melee (1977). Steve considered the 3d6 bell curve so superior that he trashed the d20 without a second thought. His roleplaying games The Fantasy Trip and GURPS use 3d6 core mechanics. Then, I struggled to grasp Steve’s dislike of the d20.

Now, I understand Jackson’s disdain, but I love D&D. Like esteemed game designers such as Jeremy Crawford and Monte Cook, I find reasons to embrace the d20.

In Cook’s designer’s notes for his Numenera RPG, he describes the d20’s flaw. “Using the d20 introduces a great deal of randomness into a game. It’s difficult to use a d20 as a task resolution die and still have character aspects play a big part in success or failure without all of a sudden finding yourself using pretty big numbers.” He gives an example like this: Suppose two archers try to hit a bullseye by rolling a 20 or higher. An untrained person with a decent 12 Dexterity gets +1 and hits 10% of the time. In comparison, a 12th-level ranger trained in the bow and boasting an 18 Dexterity gets a +8, but still only hits the bullseye 45% of the time.

D&D games show this dynamic when the DM asks everyone to roll an Intelligence (Arcana) check to recognize ancient sigils, and then the brainy wizard fails while the barbarian knucklehead succeeds. That outcome may seem funny the first time, but similar scenes play frequently and can feel disappointing. Instead of rewarding the player who chose to make a character good at something, the d20 roll often makes experts look inept.

If D&D used bigger bonuses, then experts would get a boost. Suppose the expert archer gained a +25 and hitting the bullseye required a roll of 30. Now, the sharpshooter feels more like Annie Oakley. But that arrangement makes difficult tasks impossible for unskilled characters when we really want success to become rare.

Instead of using big modifiers, fifth edition’s bounded accuracy uses modest bonuses that give every character a chance of success at the price of making experts inconsistent.

Monte describes an alternative. “Now imagine that you used 2d10 instead. 2d10 gives us a more normal distribution. In other words, you end up with a much better chance of getting a 10 than a 20. Using the same bonuses, the archer still hits the bullseye 45% of the time, but the unskilled guy only 3% of the time. That makes more sense.” With a 2d10-based game, clumsy newcomers at Faerûn athletic competitions luck into fewer medals. (In one of my very first posts, I grappled with a related issue.)

This more natural range of outcomes leads game designer Steffan O’Sullivan to write, “I’m not fond of dice systems with a flat distribution. I’m solidly in the bell-curve camp.” O’Sullivan created the Fudge RPG, which became the basis for the popular Fate system. Both games use a set of four special 6-sided dice marked on two sides with a plus (+), two with a minus (-), and two blanks. “When you need to roll dice in Fate, pick up four Fate dice and roll them. When you read the dice, read every + as +1, every blank as 0, and every – as –1. Add them all together. You’ll get a result from –4 to +4, most often between –2 and +2.” No roll requires counting past 4, so even little kids add the results easily. “The fewer mathematical calculations used to figure out a dice result, the more likely you are to stay in roleplaying,” O’Sullivan writes. “So Fudge Dice were born, and I like them a lot. They’re a joy to use and don’t slow the game down at all, one of my early design goals.” The system’s bell curve makes results of -4 and +4 rare, but possible. So a +4 (1.23%) matches my real-life chance of a bullseye, while an Olympic archer scores a bullseye on any roll better than -4.

Despite the virtues of the bell curve, Monte Cook still opted for a d20 for Numenera and D&D creators Gary Gygax and Dave Arneson chose the d20 for to-hit rolls and saving throws. The d20 rolls beautifully, it generates a big range of numbers without adding, and the icosahedron feels deliciously different from the bland cubes in countless games like Monopoly. Gygax became particularly enchanted with the exotic new dice from Japan.

Most importantly, d20s yield predictable odds compared to mechanics that combine multiple dice. Monte Cook explains, “If you’re using a system where the GM has to assign a target number for a task, it’s a lot easier to do that on the fly with a d20 than, say 3d6 or 2d10. Why? Because with a d20, the difference between, say, 17 and 18 is the same as the difference between 8 and 9. They’re basically just 5% increments. With a bell curve, that’s a lot harder to figure for the GM, particularly on the fly.”

In 1974, D&D lacked ability checks. To decide between success and failure, Gary Gygax suggested that DMs estimate the chance of success, and then improvise a roll that fits the odds. A d20 roll made the math easy.

Playing D&D means learning to embrace the d20’s swings. To help gamers love the d20, D&D’s current rules architect Jeremy Crawford offered advice on the October 3, 2019 episode of the Dragon Talk podcast. “Any time the d20 is in the mix, that is a swingy die so get ready for the unexpected. What I encourage groups, players and DMs alike to do, is rather than viewing that as something to chafe against or be unhappy about, embrace it as a storytelling opportunity. Over the years, the longer I play D&D and DM D&D, the more I have come to love the unpredictability of the d20, because so often it will create moments that will challenge the DM and the players to really stretch their storytelling ability to come up with a fun reason for why this transpired. Why did the ace rogue who triggered this battle, why did she end up going last?

“When the d20 throws you a curve ball, catch it and follow through with the curve. Just see where it leads you rather than saying, ‘this is dumb’ or ‘this isn’t how it should play out.’ No, in D&D, what the d20 does is really showing how this is going to play out. Let’s ride it and see where this craziness goes.”

If I were magically transported back to a version of 1974 that somehow lacked Gary Gygax and Dave Arneson, would my attempt to bring dungeons and dragons to the world use a d20? I might choose Fudge Dice, but I would never stop giving those new icosahedrons from Japan forlorn looks.

Related: D&D and the Role of the Die Roll, a Love Letter
When You Describe Outcomes, Flatter Your Game’s Heroes and Monsters
In D&D, Letting Everyone Roll Certain Checks Guarantees Success, So Why Bother Rolling?

The Surprising Trait Fourth Edition Shared With Original Dungeons & Dragons

The first Arduin Grimoire starts by explaining how to play Dungeons & Dragons. Sure it claims to be an explanation of how to play “a fantasy game,” but in 1976, when Dave Hargrave penned the tutorial, the range of fantasy games included D&D, D&D set in a world called Tékumel, and a game designed under the generic name of D&D until it reached stores as T&T.

Gamers needed the how-to. The original D&D rules read as a summary for people who already knew how to play. D&D arrived as a companion to a miniature battle game called Chainmail, and the rules built on a foundation of turns and moves. Gary Gygax’s peers felt comfortable with rules for inches of movement and for how many 10-foot squares a character could search in a 10-minute turn. To Gary’s audience, D&D made sense. But the rule books confused folks accustomed to rolling dice to see how many squares a wheelbarrow could move.

Hargrave’s how-to amounts to this: move, roll for monsters, repeat. If monsters appear, roll for distance, surprise, reaction, and then initiative.

As hard as D&D proved to grasp, this “sequence of play” isn’t too different from Risk. Aside from the referee, the game seems nearly as constrained as Clue—except D&D features a hidden board like Battleship.

Ken St. Andre wrote T&T—Tunnels & Trolls—because he found the D&D rules “nearly incomprehensible.” He describes T&T as having the same relationship to D&D as “Chevrolet does to Ford.” His explanation of how to play T&T worked for D&D too. “The game is played something like Battleship. The individual players cannot see the board. Only the DM knows what is in the dungeon.” In 1975, games needed boards. (See 4 popular beliefs Dungeons & Dragons defied in the 70s.)

There exist numerous enchanted tunnel complexes (call them dungeons or underworlds if you wish) that are liberally loaded with many types of treasure, and abundantly guarded by every imaginable form of monster, magic, and trap. Generally speaking, the greatest treasures and most powerful monster are found further below the surface. Brave men and women arm themselves and venture within the tunnels at risk of body and soul to seek treasure and experience.

In 1975, games also needed a way to win. St. Andre explained how. “Every time your character escapes from a tunnel alive, you may consider yourself a winner. The higher the level and the more wealth your character attains, the better you are doing in comparison to all the other players.” (See But how do you win?)

Neither D&D’s original rules nor interpreters of those rules describe the loose play of D&D today. They describe a tightly-focused game where treasure hunters enter dungeons, spend turns moving and fighting, and keep score in gold.

From 1974 through the 80s, the evolution of role-playing games marks a move from D&D’s medieval fantasy to universal systems like GURPS, the HERO System, and Basic Roleplaying. In the early 90s, universal systems peaked, and the hobby started moving toward games optimized for one genre or even a narrow range of activities. You could play Kung-fu or vampire campaigns in GURPS, but for many players, optimized systems like Feng Shui and Vampire the Masquerade offered a more compelling experience.

D&D followed the same evolution. Original D&D didn’t aim for the same scope of a modern D&D campaign. The 1974 game arrived laser-focused on dungeon expeditions—and not even on naturalistic lairs, strongholds, and tombs. Original D&D assumed multi-level undergrounds with wandering monsters and rooms stocked randomly from monster and treasure assortments. (See When megadungeons ruled Dungeons & Dragons.) The only rules for non-player characters treated NPCs as monsters to kill or as hirelings to die in dungeon crawls.

Almost everything in the little, brown books supports dungeon expeditions. Sure, the books included rules for wilderness adventures, but as a way for characters to find castle sites. The rules for castles and followers only build a bridge to another game—Chainmail. Few players crossed that bridge. Even subsequent editions of D&D largely ignored it.

As a focus, the dungeon crawl proved a massive success. Dungeons provided an evocative environment with built-in threats and rewards. Plus, dungeons kept characters on that secret board behind the DM’s screen. The walls made the game manageable for new DMs, and all but two DMs were new. (See How the dungeon crawl’s advantages propelled Dungeons & Dragons to success.)

Even though the D&D’s turns and hidden boards felt familiar to gamers in 1974, the game’s wide-open possibilities captured the imagination. In D&D, players could attempt anything. Hardly anyone held to the rigid structure or stayed in the dungeon. A city, The City State of the Invincible Overlord, became the first setting for D&D. (See A butcher, a baker, and naughty nannies in the City State of the Invincible Overlord.) By 1977, Chivalry & Sorcery offered rules for everything in a medieval fantasy world, from kings to peasants, and from jousting to courtly love. That game stemmed from a D&D campaign where players had tired of dungeons and embraced the larger world. (See Chivalry & Sorcery: What if Gary and Dave had not found the fun? Newer games with more realistic combat systems even made dungeon crawls too lethal to be a campaign’s focus. (See The Brilliance of Unrealistic Hit Points.)

As the role-playing hobby broadened, D&D’s scope grew too. By 2000, third edition arrived late to the universal system party. D&D became a branch of the d20 system, which extended to modern settings and Star Wars role playing.

By 2007, the trend toward systems optimized for a narrow range of activities reached D&D and its fourth edition. This version returned to the narrow focus of the original game, but with a completely different choice of optimal activities. Now the game focused on designing characters capable of dynamic battlefield stunts, and then showing them off in combat encounters. Dungeon expeditions became an interchangeable backdrop for combat encounters and skill challenges. This new focus drew criticism from players who felt that a miniature skirmish game, or perhaps a video game, had replaced the original role-playing game. Sure, most players knew you could run fourth edition in the same wide-open style as the prior editions, but plenty saw the new focus as a sign that D&D no longer invited role playing.

Today, D&D returns to a comfortable balance between the sharp focus of the original game and the sprawl of d20. Rather than optimize a system for a narrow focus, the game seeks to embrace three pillars of exploration, combat, and interaction. The game is bigger, but you can still dungeon crawl in the original style—as long as you can live without 10-minute turns.

Megadungeons in print and on the web

Perhaps few people play megadungeons, but my look at the era when megadungeons ruled Dungeons & Dragons and why few people play them anymore revealed great interest in vast underworlds. So in this post, I present the megadungeons in print or on the web.

To qualify for my mega-list, a dungeon must meet three qualifications. It must be…

  • in print or on the web in a form close to playable.
  • suitable for the focus of an entire campaign from low to high level.
  • too big to clear of traps and monsters, even as the focus of a campaign.

Most of these products attempt to recapture or update the play style of the original campaigns that launched D&D, so many use rules that emulate either original D&D or AD&D. If you prefer advantage, concentration, and armor classes that go up, you can play these dungeons with fifth edition. Just use the monster stats in your new manual and make up any difficulty classes as you go.

Barrowmaze product page
Barrowmaze System: Labyrinth Lord and original D&D
Tagline: Barrowmaze is a classic, old-school megadungeon.
Typical reviews: “This is a multi-year campaign in a book. It is an obvious labor of love. If this product doesn’t deserve five stars—easily deserve it—then no product deserves it.” – Greg W.

Barrowmaze is nearly a textbook example of how to make a compelling, well-presented dungeon module. – Grognardia

Rational: Underground tombs infested by chaotic cult
Snap reaction: With an emphasis on undead and dungeon factions, will Barrowmaze prove too much of a good thing?
Castle of the Mad Archmage product page
Castle of the Mad Archmage System: Adventures Dark and Deep, other games with the same initials, or Pathfinder
Tagline: Constructed to match reminiscences of Castle Greyhawk.
Typical reviews:Castle of the Mad Archmage is a lot of fun…The problem is that so much of feels either random, unexplainable, or silly.” – Dungeon Fantastic

“Serious old-school aficionados should put the Castle at the top of their shopping lists – Roles and Rules

Rational: The Mad Archmage, an insane demigod, wants it so.
Snap reaction: A tribute to Gary’s game that is best enjoyed through heavy nostalgia.
Dragon’s Delve
product now unavailable
Dragon's Delve System: d20
Tagline: Created by Monte Cook (co-designer of 3rd-Edition D&D) and written by Super Genius Games for dungeonaday.com
Typical reviews:Dragon’s Delve hits most of the right old school notes. There is in fact a great deal to like about it and I’m not ashamed to admit I may even steal an idea or three from it.” – Grognardia
Rational: Ambient magic? Insane wizards? The mysteries of Dragon’s Delve remain locked from my gaze.
Snap reaction: A mountain of interesting content locked behind the dungeonaday paywall. Update: The only trace of dungeonaday now on the web is an adventure drawn from its content, The Tomb-World of Alak-Ammur.
Castle Triskelion
product page
triskelion System: First edition Advanced Dungeons & Dragons
Tagline: Come and get a free dungeon room every day.
Typical reviews: None. You could be the first to review this product.
Rational: A feuding family who practiced abominable sorceries.
Snap reaction: A labor of love offered for free.
Castle Whiterock
product page
Castle Whiterock System: d20
Tagline: The greatest dungeon story ever told.
Typical reviews:Castle Whiterock is an epic endeavor that is the best adventuring product released by any company this year.” – Nathan C.

“The adventure features great encounters, adventure to be had, wonderful villains, great twists in the tale, and many hidden secrets waiting to be uncovered. On the down side, there are some tedious bits.” – Peter I.

Rational: Traps, magic, and monsters accumulated over the castle’s 1200-year history.
Snap reaction: No mere list of rooms, this product builds a campaign with numerous quests around a megadungeon.
Darkness Beneath
product page
The Darkness Beneath System: Original D&D and similar rules
Tagline: A multi-author megadungeon released in installments in Fight On! magazine.
Typical reviews: “The community megadungeon ‘The Darkness Beneath’ has turned out some very good levels, with a single exception.” – Ten Foot Pole
Rational: Undetermined.
Snap reaction: A strong but uneven anthology that ranges from inspired to silly, just like the old-school dungeons it emulates. The cutaway map calls me to adventure.
Dwimmermount
product page
Dwimmermount System: Labyrinth Lord, original D&D, or Pathfinder
Tagline: With Dwimmermount, the Golden Age has returned.
Typical reviews: “The very size of Dwimmermount may also be its enemy, a few forays into the place won’t discover much, and the levels get consistently weirder, but start very classically D&D.” – Dungeon of Signs

“Pages upon pages of minutiae.” – Binkystick

Rational: A dungeon set atop a node of primal chaos
Snap reaction: An attempt to recreate a golden-age play style that resists capture in print.
The Emerald Spire
product page
Emerald Spire System: Pathfinder
Tagline: An all-star superdungeon.
Typical reviews: “The superdungeon might feel like a long series of Pathfinder Society dungeons.” – 5-Minute Workday

“Two levels of the Spire really stand out for me and made me want to slice them out of the megadungeon and run them back to back as a one-shot or mini-campaign.” – Tor.com

Rational: An insane creature of immense power living at the bottom level.
Snap reaction: This collection of levels created by all-star contributors probably plays better if you divide the levels into separate dungeons.
Eyes of the Stone Thief
product page
Eyes of the Stone Thief System: 13th Age
Tagline: The Stone Thief rises. Enter it, find its secrets and defeat it–or die trying.
Typical reviews: “A very, very clever idea executed very well.” – The Other Steve

“The book as a whole also gives you the tools and tips to customize [the campaign] for your players.” – Addison Recorder

Rational: The dungeon is alive.
Snap reaction:  A promising example of the living-dungeon concept, backed with advice on running and customizing parts or as a campaign.
Grande Temple of Jing
product page
Grand Temple of Jing System: Pathfinder
Tagline: The dungeoncrawl that rules them all!
Typical reviews: None. This product hasn’t been released yet.
Rational: A temple to a trickster god
Snap reaction: With a catch-all concept and many contributors, expect a trap- and puzzle-filled dungeon loaded with ideas.
Greyhawk Ruins
product page
Greyhawk Ruins System: Second edition AD&D
Tagline: Enter the infamous ruins of Castle Greyhawk, the most formidable and expansive dungeon on Oerth.
Typical reviews:Greyhawk Ruins may not be a particularly inspired example of a megadungeon, but it is a megadungeon and I give it points for that alone.” – Grognardia

“A classic, illogical ‘gilded hole’ dungeon.” – Lawrence Schick, Heroic Worlds

Rational: The wizard Zagag’s mad experiments
Snap reaction: The product every player dreamed of in the 70s, released in 1990 when our expectations had changed.
Rappan Athuk
product page
Rappan Athuk System: Swords & Wizardry, original D&D, or Pathfinder
Tagline: Nothing more and nothing less than a good, old-fashioned dungeon crawl.
Typical reviews: “A TON of interesting encounters and levels. It’s also maddeningly confusing in places” – Ten Foot Pole

“I’ve been somewhat underwhelmed by a couple of levels, but at the same time, I’ve really, really liked several ideas herein.” – Thilo G.

Rational: A complex created by refugee priests of Orcus
Snap reaction: Suited to old-school DMs who somehow recruit the rare players who enjoy dungeon-only campaigns, high body counts, and unwinnable final encounters.
The Ruins of Undermountain
The Ruins of Undermountain System: Second edition AD&D
Tagline: The deepest dungeon of them all.
Typical reviews: “The dungeon itself is barely detailed, with only the major level features written up.” – Dungeon Fantastic
Rational: Another insane wizard
Snap reaction: An outline for a DM determined to create a megadungeon in the Forgotten Realms and willing to dream up the details.

Stonehell
product page
Stonehell System: Labyrinth Lord and original D&D
Tagline: Enough monsters, traps, weirdness, and treasure to keep you gaming for a long, long time.
“Stonehell Dungeon: Down Night-Haunted Halls is probably the best megadungeon published to date in any form” – Grognardia

Stonehell takes a curious middle ground between detailed set pieces, and leaving some room descriptions sparse to allow for DM improvisation.” – Dreams in the Lich House

“This is certainly one of the best works to come out of the OSR. It’s a megadungeon and it’s close to perfect.” – Ten Foot Pole

Rational: A prison where the pain and suffering attracted a powerful, chaotic entity.
Snap reaction: Highly touted by old-school fans. Adopts a concise presentation inspired by 1-page dungeon design.
World’s Largest Dungeon
product page
World's Largest Dungeon System: d20
Tagline: Over 16,000 Encounters – A mammoth dungeon unlike any other! Every monster in the SRD – And a few you’ve never seen before!
Typical reviews: “Nothing remarkable or all that memorable about it” – Jeremy Reaban

“They don’t expect you to actually run the World’s Largest Dungeon as one big dungeon. Considering that’s the only reason that anyone would actually buy the product, I find that pretty stupid.” – oriongates

Rational: A giant prison for evil.
Snap reaction: Not so much an adventure as a publishing stunt.