Tuesday, 14 December 2010

Find traps or FIND TRAPS

I’m confused and this post will hopefully allow me to get my thoughts in order and make a coherent house rule.

Dwarves can find traps, so can thieves. What are the differences?

Let’s start with B/X

Traps (B22)
“Dungeons often contain traps, such as a trap door in the floor which springs open when a character walks over it. If any character does something which could trigger a trap (such as walking over a certain point), the trap will be sprung on a roll of 1-2 (on 1d6)…
Any character has a 1 in 6 chance of finding a trap when searching for one in the correct area. [16.6%] Any dwarf has a 2 in 6 chance. (This does not apply to magical traps, such as sleep trap.) Checking a specific area for a trap will take one one full turn. The DM should only check for finding a trap if a player says that the character is searching for one. Each character may only check once to find each trap.”

Thieves (B8)
“Find or Remove Traps is a double ability. The thief has the listed chance of finding a trap (if there is one) and the same chance (if the trap is found) of removing it. Either attempt may only be tried once per trap.” [1st level thief 10%, 2nd level thief 15% and 3rd level thief 20%, which means the thief only surpasses a 1 in 6 chance at 3rd level.]

Dwarves (B9)
“They are expert miners and are able to find slanting passages, traps, shifting walls, and new construction one-third of the time (a roll of 1 or 2 on 1d6) when looking for them.” [my emphasis]

Stock the Dungeon (B52)
Room Traps:
Poison gas: Save vs Poison or die
Fog: Looks like Poison gas, but harmless
Pit: 1d6 points of damage per 10’ fallen
Ceiling Block falls: Save vs Turn to Stone or take 1d10 points of damage [nice use of a saving throw here as opposed to the ubiquitous d20 vs dexterity]
Pendulum blade from ceiling: 1d8 points of damage
Chute: No damage, but slide to the next level down

Treasure Traps:
Poison needle: Save vs Poison or die
Spring-fired darts: 1-6 darts hit for 1-4 points of damage each [more chance of a first level thief surviving the save vs poison or die, then these darts!]
Spray: Be sprayed with an unknown liquid that attracts Wandering Monsters; double chances for 1d6 hours [this is cool, I’ve never used before but I like it!]
Illusion: Anything, often a monster (as phantasmal force)

From the above Robert Fisher (who I much admire see my previous post) makes the following ruling:
Anybody can search for traps. Dwarfs have a 2 in 6 chance. Everyone else has a 1 in 6 chance. (p.B22). Thieves use the 1 in 6 chance until 3rd level when their F&RT skill becomes more favorable. The 1st & 2nd level thieves, however, must use their less favorable F&RT skill when attempting to disarm a trap.
I’ll make a number of observations:
Traps (B22) appears to imply LARGE Room traps not intricate needle in the treasure chest traps. Moldvay basic was concerned about the dungeon. I wonder what he would have said if he was talking about wilderness encounters. Unfortunately Cook Expert doesn’t discuss traps. My question to myself and to Robert Fisher is, can dwarves detect forest traps, can dwarves detect small Treasure Traps, or can only thieves?


Dwarves (Basic DMR 15)
"Because of their mining experience, dwarves can sometimes recognize special dungeon features made of stone or wood, such as
(1) sloping passages
(2) shifting walls
(3) new constructions
(4) traps
The traps a dwarf can find are those involving large dungeon features, such as a falling ceiling, floor pit, and so forth. The traps a dwarf may discover does not refer to all traps. For example, a dwarf would have no chance at detecting a small dart trap on a chest; this could be detectable only by a thief."

While it is possible to conclude that this is Mentzer that was Moldvay I think this overlooks two key points: 1) Mentzer wrote with a clear vision of the future books in his series, each book was meant to build off the previous and 2) Neither Mentzer and Moldvay wrote in a D&D vacuum, they lived and breathed D&D and were well known to Gygax and the original players. What I am saying is that I think Mentzer is merely making explicit what Moldvay would already have agreed with. Indeed Robert Fisher might also say to me that this posting is just making explicit what he always believed, that dwarves and presumably everyone else on a 1in6, can only detect dungeon traps.

Let’s look for other assistance:

Dr Holmes
Page 6
“[Thieves can]… remove small traps such as poisoned needles.”
Underground, [dwarves] can detect slanting passages, traps, shifting walls and new contruction about one-third of the time.” [my emphasis]

Original D&D
M&M page 7
“[Dwarves] note slanting passages, traps, shifting walls and new construction in underground settings.” [my emphasis]
M&M Page 10
“Strength will also aid in opening traps and so on.” [really, how exactly?]
Underworld Page 9
Traps are usually sprung by a roll or a 1 or a 2 when any character passes over or by them. Pits will open in the same manner.
Supp 1 Page 4
“[Thieves can] remove small trap devices (such as poisoned needles)”.

DMG page 19
Thief abilities: “Small or large traps can be found, but not magical or magically hidden traps.”
DMG page 20
“Simple mechanical traps can be set by thieves or assassins.”
PH page 15-16
“Dwarves are miners of great skill. They are able to… detect traps involving pits, falling blocks and other stone work.”

Allston / Rules Cyclopedia
Page 261
“A trap is anything that could cause damage, delay or a magical effect to occur. The trap may be found, and possibly removed, by a thief character.”
Page 24
“Dwarves can sometimes detect traps (specifically, traps built into stonework or heavy construction, not other types of traps such as rope-traps in the forest or spring-out needles built into a jewelry box.”

Shall I bring all this together with a few observations:

So much for all singing from the same hymn sheet – the founders of D&D appear as confused as I do
The everyone can detect traps, 1 in 6 chance, rule of Moldvay basic I can not find repeated anywhere in other editions. But I like it, it’s simple and in keeping with other character abilities such as find secret doors, hear noise and open doors. If characters are being particularly sensible, using a 10’ poles for instance, it allows the DM to easily add a positive modifier to the d6 roll.
There is a strong recurrent theme that dwarves can only detect underground traps.
What types of traps thieves can detect, is up for debate. But the thought of limiting them to only small, treasure like traps, removes a potential strong advantage of having a thief in one’s party for exploration. I keep imagining how useful a thief companion would be for Indiana Jones, though in my opinion Indiana Jones fits the D&D thief archetype better than he does the fighter, despite the fights he engages in.

My house rule

Large Traps (Room/Underground or Wilderness Traps)
Small Traps (Treasure Traps)

Anyone can detect Large Traps with a 1 in 6 chance.
Dwarves can detect Large Traps when underground with a 2 in 6 chance.

Only thieves can detect Small Traps
Until 3rd level thieves use their 1 in 6 chance to detect/find Large Traps but must use the given thief ability percentage roll to remove the trap.
Small Traps always use the given thief ability percentage roll at all levels, to both find and remove traps.

I just call the detection of slanting passages, traps, shifting walls, and new construction; dwarf sense, which is available when the dwarf is underground or around stone work and works on a 2 in 6 chance. 

PS A kind welcome to Gothridge Manor and ze bulette of Dungeons and Digressions . I am particularly chuffed because I read your blogs already.


  1. Well-analyzed! I just checked the Labyrinth Lord core rulebook and found that the same ambiguity you note in B/X persists there: all characters except dwarves detect traps on a 1 in 6, dwarves do so on a 2 in 6. But Proctor's language strongly implies what you call Large Traps: "Players must declare that their characters are actively looking for traps, and they must be looking in the right place. This roll may only be made once in a particular location, and it takes 1 turn per effort made" (p. 45). "Location" sounds like a sector of a room, and the rule is worded much like the LL rule for searching for secret doors.

    Great houserule!

  2. Yeah. I think that’s a perfectly valid interpretation. I might even argue that that is the intent of the rules.

    At my table, though, I choose a looser interpretation. Similar to how I allow the Wisdom modifier to be applied to all saving throws.

  3. I'm honoured Robert, thank you for commenting.

  4. Thanks for the welcome.I've always interpreted the dwarves finding traps like pits possible hidden area in walls, anything architectural pretty much where thieves have can identify traps in general. But I also through in a caveat for mages that they may ID magical traps. And fighters have a chance of detecting an ambush, which is sorta a trap. Kinda sorta.