Appendix A:
Random Dungeon Generation

- - - - - Start Areas - - - - -
I.: Periodic Check - - - - - - - - - -
II.: Doors - - - - - - - - - -
III.: Side Passages III.A.: Passage Width Table III. B.: Special Passage - - - - - - - -
IV.: Turns - - - - - - - - - -
V.: Chambers and Rooms Shape and Size V.A.:
Unusual Shape
Unusual Size
V.C.: Number of Exits V.D.: Exit Location V.E.: Exit Direction V.F.: Chamber or Room Contents V.G.: Treasure V.H.: Treasure is Contained In V.I.: Treasure is Guarded By V.J.: Treasure is Hidden By/In
VI.: Stairs - - - - - - - - - -
VII.: Trick/Trap VII.A.: Gas Sub-Table - - - - - - - - -
VIII.: Caves and Caverns VIII.A.: Pools VIII. B.: Lakes VIII.C.: Magic Pools - - - - - - -
- - - - - Random Dungeon Generation for Solo Play - - - - -
Appendices - - - - - - - - - DMG

When you need help in designing a dungeon - whether it is a level in
your main dungeon || a labyrinth discovered elsewhere - the following
random generation system has proven itself to be useful. It must be noted
that the system requires time, but it can be used directly in conjunction
with actual play.

The upper level above the dungeon in which adventures are to take place
should be completely planned out, and it is a good idea to use the outdoor
encounter matrix to see what lives where (a staircase discovered later just
might lead right into the midst of whatever it is). The stairway down to the
first level of the dungeon should be situated in the approximate middle of
the upper ruins (or whatever you have as upper works).

The first level of the dungeon is always begun with a room; that is, the
stairway down leads to a room, so you might go immediately to TABLE V.
and follow the procedure indicated or use one of the following ”starter”
areas. Always begin a level in the middle of the sheet of graph paper.

Keep a side record of all monsters, treasures, trick/traps, and whatever -- a
normal dungeon matrix.

Discretion must prevail at all times. For example: if you have decided that
a level is to be but one sheet of paper in size, and the die result calls for
something which goes beyond an edge, amend the result by rolling until
you obtain something which will fit with your predetermined limits.
Common sense will serve. If a room won’t fit, a smaller one must serve,
and any room or chamber which is called for can be otherwise drawn to
suit what you believe to be its best positioning.


Die Result
1-2 Continue straight -- check again in 60' (this table)
3-5 Door (see TABLE II.) 
6-10 Side Passage (see TABLE III.) -- check again in 30' (this table)
11-13 Passage Turns (see TABLE IV., check width on TABLE IIIa.) -- check again in 30' (this table) <corrected to: 3a>
14-16 Chamber (see TABLE V.) -- check 30' after leaving (this table) 
17 Stairs (see TABLE VI.) 
18 Dead End (walls left, right, and ahead can be checked for Secret Doors, see TABLE V.D., footnote)
19 Trick/trap (see TABLE VII.), passage continues- check again in 30' (this table)
20 Wandering Monster, check again immediately to see what lies ahead so direction of monster's approach can be determined.


Location of Door               Space Beyond Door Is:
Die Result Die Result
1-6 Left 1-4 Parallel passage**, or 10 ' x 10' room if passage straight ahead 
7-12 Right 5-8 Passage straight ahead 
13-20 Ahead 9 Passage 45 degrees ahead/behind***
- - 10 Passage 45 degrees behind/ahead*** 
- - 11-18 Room (go to TABLE V.) 
- - 19-20 Chamber (go to TABLE V.)

                                                               Always check width of passage

 * Check again immediately on TABLE I. unless door is straight ahead; if another door is not indicated, then ignore the result and check again
30' past the door. If a room or chamber is beyond a door, go to TABLE V.

**Extends 30' in both directions.

***The direction will be appropriate to existing circumstances, but use the
direction before the slash in preference to the other.


Die Result
1-2 left 90 degrees 
3-4 right 90 degrees 
5 left 45 degrees ahead 
6 right 45 degrees ahead 
7 left 45 degrees behind (left 135 degrees) 
8 right 45 degrees behind (right 135 degrees) 
9 left curve 45 degrees ahead 
10 right curve 45 degrees ahead 
11-13 passage "T"s
14-15 passage "Y's 
16-19 four-way intersection 
20 passage "X"s 
    (if present passage is horizontal or vertical it forms a fifth passage into the "X") 

Die Result
1-12 10'
13-16 20'
17 30'
18 5'


Die Result
1-4 40', columns down center
5-7 40', double row of columns
8-10 50', double row of columns
11-12 50', columns 10' right and left support 10' wide upper galleries 20' above*
13-15 10 ' stream**
16-17 20' river***
18 40' river***
19 60' river***
20 20', chasm****

* Stairs up to gallery will be at end of passage (1-15) or at beginning (16-20).
In the former case if a stairway is indicated in or adjacent to the passage it will replace the end stairs 50% (1-10) of the time and supplement 50% (11-20) of the time.

** Streams bisect the passage. They will be bridged 75% (1-15) of the
time and be an obstacle 25% (16-20) of the time.

*** Rivers bisect the passage. They will be bridged 50% (1-10) of the
time, have a boat 25% (11-15) of the time (50% chance for either
bank), and be an obstacle 25% of the time.

**** Chasms bisect the passage. They are 150' to 200' deep. They will be
bridged 50% (1-10) of the time, have a jumping place 5'-10' wide
25% (1 1-15) of the time, and be an obstacle 25% (16-20) of the time.


Die Result
1-8 left 90º
9 left 45º ahead
10 left 45º behind (left 135 degrees)
11-18 right 90º
19 right 45º ahead
20 right 45º behind

    (Roll for Shape, Size, and Exits; then Contents, Treasure, and how the latter is contained, if applicable.)
Die Chamber Shape and Area <(Optional: Exits are Doors)> Room Shape and Area <(Optional: Exits are Passageways. Passage Width.)>
1-2 Square, 20'x20' Square,10'x10'
3-4 Square, 20' x 20' Square, 20' x 20' 
5-6 Square, 30' x 30' Square, 30' x 30'
7-8 Square, 40' x 40' Square, 40' x 40' 
9-10 Rectangular, 20' x 30' Rectangular, 10' x 20' 
11-13 Rectangular, 20' x 30' Rectangular, 20' x 30' 
14-15 Rectangular, 30' x 50' Rectangular, 20' x 40'
16-17 Rectangular, 40' x 60' Rectangular, 30' x 40'
18-20 Unusual shape and size - see sub-tables below  Unusual shape and size - see sub-tables below 

Die Shape
1-5 Circular*
6-8 Triangular
9-11 Trapezoidal
12-13 Odd-Shaped**
14-15 Oval
16-17 Hexagonal
18-19 Octagonal
20 Cave

* 1-5 has pool (see TABLE VIII. A. and C. if appropriate), 6-7 has well, 8-10 has shaft, and 11-20 is normal.
** Draw what shape you desire or what will fit the map - it is a special.

Die Size
1-3 about 500 sq. ft.
4-6 about 900 sq. ft.
7-8 about 1300 sq. ft.
9-10 about 2000 sq. ft.
11-12 about 2700 sq. ft.
13-14 about 3400 sq. ft.
15-20 roll again and add result to 9-10 above (if another 15-20 repeat the process, doubling 9-10 above, and so on)

    TABLE V.C.: NUMBER OF EXITS (d20) <(Optional: 50% chance of exit on each wall. Randomly generate square of exit. eg. d3 if the wall is 30'.)>
Die Room Area Number of Exits
1-3 up to 600' 1
1-3 over 600' 2
4-6 up to 600' 2
4-6 over 600' 3
7-9 up to 600' 3
7-9 over 600' 4
10-12 up to 1200' 0*
10-12 over 1200' 1
13-15 up to 1600' 0*
13-15 over 1600' 1
16-18 any size 1-4
19-20 any size 1 -- door in chamber, passage in room

* Check once per 10' for secret doors (see TABLE V. D., footnote).

Die* Location
1-7 opposite wall
8-12 left wall
13-17 right wall
18-20 same wall

* If a passage || door is indicated in a wall where the space immediately beyond the wall has already been mapped,
then the exit is either a secret door (1-5) or a one-way door (6-10) or it is in the opposite direction (11-20).

Die Direction (if a Door use TABLE II instead) -- check for width on TABLE III A
<"1 -- door in chamber, passage in room">
1-16 straight ahead
17-18 45 degrees left/right*
19-20 45 degrees right/left*

* The exit will be appropriate to existing circumstances, but use the direction before the slash in preference to the other.

    TABLE V. F.: ROOM CONTENTS (d20) <(5f)> <(Optional: Roll TWICE on this table.)>
Die Contents
1-12 empty
13-14 Monster only (determine on appropriate table from APPENDIX C: RANDOM MONSTER ENCOUNTERS, Dungeon Encounter Matrix).
15-17 Monster && treasure (see TABLE V.G. below) 
18 Special*, 
or contains stairway up 1 level (1-5), up 2 levels (7-8), down 1 level (9-14), down 2 levels (15-19), or down 3 levels -- 2 flights of stairs and a slanting passageway (20). 
19 Trick/trap (see TABLE VII.) 
20 Treasure (see TABLE V.G..)

* Determine by balance of level or put in what you desire; otherwise put in stairs as indicated.

    TABLE V. G.: * (d20) <(5g)>
Die Without Monster With Monster
01-25 1,000 copper pieces/level Take two rolls on "Without Monster" Table, 
add 10% to the total of each roll.
26-50 1,000 silver pieces/level -
51-65 750 electrum pieces/level -
66-80 250 gold pieces/level -
81-90 100 platinum pieces/level -
91-94 1-4 gems/level -
95-97 1 piece jewelry/level -
98-00 Magic (roll once on Magic Items Table) <> -

* See also TABLES V. H. and I. or J.
<(Optional: 50% chance to check I or J).>

Die Result
1-2 Bags
3-4 Sacks <large, small>
5-6 Small Coffers
7-8 Chests <PH: Chest, wooden, large - 17 sp | Chest, wooden, small - 8 sp> <Chest (empty) - 25#>
9-10 Huge Chests
11-12 Pottery Jars
13-14 Metal Urns
15-16 Stone Containers
17-18 Iron Trunks
19-20 Loose

* Go to TABLE V.I. on a roll of 1-8, TABLE V.J. on a 9-20 to determine protection if desired.
<(Optional: 50% chance to check I or J).>

Die Result
1-2 Contact poison on container 
3-4 Contact poison on treasure 
5-6 Poisoned needles in lock 
7 Poisoned needles in hondles 
8 Spring darts firing from front of container 
9 Spring darts firing up from top of container 
10 Spring dartsfiring up from inside bottom of container 
11-12 Blade scything across inside 
13 Poisonous insects or reptiles living inside container <(Snake, poisonous)>
14 Gas released by opening container 
15 Trapdoor opening in front of container 
16 Trapdoor opening 6' in front of container 
17 Stone block dropping in front of the container
18 Spears released from walls when container opened 
19 Explosive runes
20 Symbol


Die Result
1-3 Invisibility
4-5 Illusion (to change or hide appearance)
6 Secret door under container
7-8 Secret compartment in container
9 Inside ordinary item in plain view
10 Disguised to appear as something else
11 Under a heap of trash/dung
12-13 Under a loose stone in the floor
14-15 Behind a loose stone in the wall
16-20 In a secret room nearby


Die Result
1-5 Down 1 level* 
6 Down 2 levels**
7 Down 3 levels***
8 Up 1 level 
9 Up dead end (1 in 6 chance to chute down 2 levels) 
10 Down dead end (1 in 6 chance to chute down 1 level) 
11 Chimney up 1 level, passage continues, check again in 30' 
12 Chimney up 2 levels, passage continues, check again in 30' 
13 Chimney down 2 levels, passage continues, check again in 30' 
14-16 Trap door down 1 level, passage continues, check again in 30' 
17 Trap door down 2 levels, passage continues, check again in 30' 
18-20 Up 1 then down 2 (total down 1), chamber at end (roll on TABLE V.)

* 1 in 20 has a door which closes egress for the day.
** 2 in 20 has a door which closes egress for the day.
*** 3 in 20 has a door which closes egress for the day.

N.B. Check for such doors only after descending steps if playing solo!

    TABLE VII.: TRICK/TRAP (d20) <(Optional: d6, 1-3 = TRICK, 4-6 = TRAP)>
Die Result
1-5 Secret Door unless unlocated
Non-elf locates 3 in 20, elf locates 5 in 20, magical device locates 18 in 20 (then see TABLE II.). 
Unlocated secret doors go to die 6,7 below. 
6-7 Pit, 10' deep, 3 in 6 to fall in. 
8 Pit, 10' deep with spikes, 3 in 6 to fall in.
9 20' x 20' elevator room (party has entered door directly ahead and is in room), 
descends 1 level and will not ascend for 30 turns. 
10 As 9. above, but room descends 2 levels. 
11 As above, but room descends 2-5 levels -- 
1 upon entering and 1 additional level each time an unsuccessful attempt at door opening is made, 
or until it descends as far as it can. 
This will not ascend for 60 turns. 
12 Wall 10' behind slides across passage blocking it for from 40-60 turns. 
13 Oil (equal to one flask) pours on random person from hole in ceiling, followed by flaming cinder (2.12 h.p. damage unless successful save vs. magic is made, which indicates only 1-3 h.p. damage). 
14 Pit, 10' deep, 3 in 6 to fall in, pit walls move together to crush victim(s) in 2-5 rounds. 
15 Arrow trap, 1-3 arrows, 1 in 20 is poisoned. 
16 Spear trap, 1-3 spears, 1 in 20 is poisoned. 
17 Gas; party has detected it, but must breathe it to continue along corridor, as it covers 60' ahead. 
Mark map accordingly regardless of turning back or not. (See TABLE VII. A.) 
18 Door falls outward causing 1-10 hit points, 
or stone falls from ceiling causing 2-20 hit points of damage to each person failing his saving throw versus petrification. 
19 Illusionary wall concealing 
8. (pit) above (1-6), 
20. (chute) below (7-10)
or chamber with monster and treasure (11-20) (see TABLE V., 15-17). 
20 Chute down 1 level (cannot be ascended in any manner). 

Die Result
1-7 Only effect is to obscure vision when passing through.
8-9 Blinds for 1-6 turns after passing through.
10-12 Fear: run back 120' feet unless saving throw versus magic is  made.
13 Sleep: party sound asleep for 2-12 turns (as sleep spell). 
14-18 Strength: adds 1-6 points of strength (as strength spell) to all fighters in party for 1 to 10 hours.
19 Sickness: return to surface immediately. 
20 Poison: killed unless save vs. poison is made.

CAVES && CAVERNS FOR LOWEST LEVELS: You may wish to have
"roughhewn" and natural tunnels in lower levels, and where rooms and
chambers are indicated substitute Caves and Caverns. Exits are as above.

Die Result
1-5 Cave about 40' x 60'
6-7 Cave about 50' x 75'
8-9 Double Cave: 20' x 30', 60' x 60'
10-11 Double Cave: 35' x 50', 80' x 90'*
12-14 Cavern about 95' x 125'*
15-16 Cavern about 120' x 150'
17-18 Cavern about 150' x 200' *
19-20 Mammoth cavern about 250'-300' X 350'-4W**

* Roll to see if pool therein (see TABLE VIII.A.).

** Roll to see if lake therein (see TABLE VIII.B.).

    TABLE VIII. A.: POOLS (d20)

Stephen Youll - The Man Who Stayed Behind.jpg
Die Result
1-8 No pool
9-10 Pool, no monster
11-12 Pool, monster
13-18 Pool, monster, and treasure
19-20* Magical pool

    TABLE VIII B.: LAKES (d20)
Die Result
1-10 No lake
11-15 Lake, no monsters
16-18 Lake, monsters*
19-20 Enchanted lake**

* Determine monster and treasure from appropriate encounter matrix.

** Enchanted lake leads any who manage to cross i t to another dimension,
special temple, etc. (if special map is available, otherwise treat as lake
with monsters), 90% chance that monster will guard lake.

Die Result
1-8 Turns gold to platinum (1-11) or lead (12-20), one time only.
9-15 Will, on a one-time only basis, add (1-3) or subtract (4-6) from one characteristic of all who stand within it: 
    1 = STR
    2 = INT
    3 = WIS
    4 = DEX
    5 = CON
    6 = CHA
(add or subtract from 1-3 points, checking for each character as to addition or subtraction, characteristic, 
and amount). 
16-17 Talking pool which will grant 1 wish to characters of its alignment 
and damage others from 1-20 points. Wish can be withheld 
for up to 1 day. Pool's alignment is: lawful good 1-6, 
lawful evil 7-9, chaotic good 10-12, chaotic evil 13-17, 
neutral 18-20. 
18-20 Transporter pool: 1-7, back to surface; 8-12, elsewhere on level; 
13-16, 1 level down; 17-20, 100 miles away for outdoor adventure. 

* In order to find out what they are, characters must enter the magic pools.


The random dungeon generation system is easily adaptable to solitary play.
Locate the entrance to the dungeon, and then select one of the random dungeon starting areas given here, locating it in the middle of the graph paper.

Monsters: Inhabitants of the dungeon are determined from the DUNGEON ENCOUNTER MATRIX.
For special areas you can have a friend || correspondent send you sealed information.

Listening at Doors: Use a d12, and if a 1 is rolled, there is a
monster (with or without treasure). Procedure is then normal, but surprise
is possible only on the monster's part.

ESP and Other Detection Devices: Use a 6-sided die, a 1 indicating a
monster which will be known -- roll it out, ignoring any undead or other
non-thinking monsters. Check other rooms, chambers, etc. normally and
for any monster which can not be indicated by the ESP or detection device
surprise is only possible on a roll of 1 on an 8-sided die.

(2) Did you (or do you) use the dungeon generation material (in the DMG) much? Or were most campaigns and dungeons very carefully crafted?

Thank you again!!

I seldom used the random dungeon generation system, although I found it useful on a few occasions.
That said, I wouldn't call most of my dungeon levels "carefully crafted."
Especially themed ones were, and I did my best to make all of them confusing to map, but that's more workmanlike than otherwise.
The encounters were likewise a mix or "whatever" and "this will knock their sox off" sorts, but some features of many thrown together as mere mazes levels, had specially designed and placed features.


Fid wrote:

When making Castle Greyhawk and other dungeon maps in "ye olden tymes", did you ever rely on the Random Dungeon Generation tables in the 1e DMG (or something similar) as a starting point?

No, not for Castle Greyhawk. There I always had an idea in mind, frew out each level with ruler and template.

I did use random dngeon generation for such places discovered in oytdoor adventuring by the PC party.


serleran wrote:
Did you ever use the random dungeon creation system found in the OAD&D DMG?
That section has always been something of great interest to me (so much, in fact, I wrote my own soon to be published by our Trollish friends.)


But of course.

What appears in the DMG is the result of my devising and using the random dungeon generation system 
I just didn't use it very often with my player group, as I had lots of dungeon levels ready to go.
It came in handy when a dungeon was discovered during a free-form outdoor adventure.


Originally posted by MerricB
I've just been using your Random Dungeon tables in the 1E DMG to create an "on-the-fly" dungeon for my players, due to a couple of decisions they made that surprised me.

Lots of fun was had by all - I must thank you heartily for those tables, and the additional suggestions for tricks in the DMG appendices! A couple of 'elevator' rooms have confused the mapper mightily, and the final encounter with an intelligent throne with the powers of sex-change, gem-granting and teleportation have led to a cliff-hanger where the mapper has been teleported off onto a solo quest. The other characters haven't yet realised he has the only map... 

Happy to hear that, and I did indeed use the same for more than a few "scratch" adventures done on the fly.
I feeely admit I love to DM dungens where exploration is at least as important as the encounters, solving the problems and defeating the tricks and traps a major feature of the whole.

Rob had some very nasty stuff like that in his dungeons, and I swan I am still at a loss as to one.
It seemed every time my PC would pick up a loose gem--usually not more than 1-100 GP value, but sometimes greater, so the lure was irrestible--he'd soon be teleported to some other place, sometimes a most unpleasant one.
Never did figure out if it was the gems proper or some other nearby thing that activated the transferrance 

Originally Posted by Wolv0rine
When the time finally comes (may it be far, far off) I think someone with loads of cash should build an E. Gary Gygax Museum designed with the Random Dungeon Generator from the 1E DMG

Now there's an idea 
A subterranean fun house, where the "treasures" gained from succeeding in getting past the encounters would be viewing exhibits with my stuff on display, maybe a pic of the "victor" doing so as proof of success.


Originally Posted by mistere29
Gary, i read in an old interview

"by creating the village of Hommlet and the temple [sic] of Elemental Evil to test some ideas I had about random dungeons, and outdoor terrain so forth."

Could you eleaborate a bit on this. Was the pre-Metzner draft largely designed by the random tables in the dmg?


The village and main temple areas were carefully mapped before I began adventure sessions in the area.
The random generation was used mainly in developing the land around the village and some of the side areas surrounding the main rooms I had done for the temple dungeons.

As a side note, the random tables worked quite well, but they took too long.
I found that it was easier and quicker for me to just bash ahead as usual and put in whatever I liked at the moment.