The Thief in Old School D&D

The Thief in old school editions of Dungeons & Dragons has been picked apart and written about at length elsewhere, but because I have been running B/X D&D with the intent of hewing as close to the rules as written as possible, I’ve been thinking about thieves a lot lately. So I’m throwing my hat into the ring with this Thief post, as much to solidify my understanding of the class as anything else. It might be impossible to reach definitive conclusions about anything in early D&D, mostly because the attitude around the game was very much do what you want with it,” but as someone interested in rules and game systems, I think it is worth digging into the nitty gritty. This is less an essay or a statement about how I think the Thief should be run, and more of an exploration of my current interpretation.

Whence the Thief

First, a history lesson. While the Thief appears very early in the history of D&D, the class was not part of the original three booklets, released in 1974. There were only three classes in the original game: Fighting-Man, Cleric, and Magic-User.

The Thief came soon afterwards, an addition to the game first conceived by Gary Switzer, who gamed at Aero Hobbies in Santa Monica, California. After talking with Switzer, Gary Gygax decided to incorporate the class into the game, and the Thief saw official widespread distribution in D&D’s first supplement, Greyhawk.

The Thief’s most notable feature compared to other classes is a list of specific skills & actions which the Thief can attempt, usually by rolling under a certain number on a d100. These percentage-based abilities are the first example of a detailed skill system in a role playing game, and are the source of much hand-wringing.

There are some die-hard Original D&D fans out there who insist that by introducing a skill system, the Thief shifts focus away from players being creative in description and towards looking at numbers on a character sheet, and is therefore the beginning of the end of RPGs being any good. RIP Tabletop Roleplaying, 1974-1975.

[caption id=“attachment_404” align=“aligncenter” width=“447”]The cover of Greyhawk (1975) Supplement I: Greyhawk (1975)[/caption]

My Thief is Terrible at Thievery

The obvious complication with the Thief is that at low levels, all of their abilities look like straight up garbage, except climb sheer surfaces.” If you don’t know, thief abilities are presented as a table, mostly of percentage rolls. It looks like this:

[caption id=“attachment_381” align=“aligncenter” width=“793”] Thief Skills table detail from B/X Essentials[/caption]

So you have Climb Sheer Surfaces” which starts really high and then increases marginally each level, and then a whole bunch of numbers which seem really low for anyone claiming to be a professional thief. If you know your pulp fantasy, climbing really well probably comes straight to us from The Tower of The Elephant, a Conan story by Robert E. Howard in which Conan and another thief climb deftly into a tower to steal stuff and end up encountering Robert E. Howard’s xenophobia disguised as an alien god thing.

Hear Noise” actually makes sense in the context of the other rules. Most characters have a 1-in-6 chance of hearing noises behind a door, and I read that as their chance of doing it on a single turn. Players can choose to sit still and listen for a few turns to up their chances, but obviously they risk those random encounter rolls. It’s a tradeoff that makes sense.

Outside of climbing and hearing, it’s not super clear how to use these abilities in a way that makes playing a thief at all reliable or fun. For a real understanding of the Thief though, context is important, and in the B/X context you have to look at each PC as part of a cohesive whole, the party, and less as someone who is going to be doing awesome stuff on their own.


Anyone who had played B/X and talked about it online has an opinion about how these are supposed to work, and none of them seem completely ideal to me. Usually people end up with some variation on the Thief being better at everyone at these things, and their better-ness being indicated by a percentage. I.E. Anyone can try to sneak, but the Thief has a 20% chance to be completely, supernaturally silent. I get why people arrive here, but it isn’t satisfying to me,  mostly because I don’t find any support for that reading in the text. And while making rulings is a vital part of the whole B/X thing, I’m trying to get as close as possible to the original intended experience produced by the rules.

Anyone of any class being able to try sneak probably means making an ability check, I.E. rolling equal to or under their Dexterity on a D20. Ability checks aren’t really a core mechanic in B/X as written though, and they don’t even appear in OD&D. They are a useful tool, but kind of an afterthought. I try to use them sparingly when I play.

This may be blasphemy when it comes to how we think about role playing games now, but when it comes to B/X, I am actually relatively comfortable with the interpretation that only Thieves can try and be sneaky, and that attempting to sneak is in and of itself a pretty special power in the context of the B/X rules, even if you only have a 20% chance of success.

Despite the whole each player controls a single character thing, B/X is still a game that hews pretty close to its wargaming roots, in that it often feels as though the players are collaborating in controlling a whole group or expedition, as much as they are their individual characters. The rules as written really don’t care about the agency or actions of a single character as much as they do about the actions of the party as a whole, cohesive unit. The party moves through the dungeon at a certain speed each turn. The caller related the decisions and actions of the party to the DM. Most importantly in this case, the DM rolls when monsters are encountered to see if either the monsters or the party are surprised. As written, that value is fixed. Surprise happens on a one or a two, regardless of how sneakily a given player described their actions, or how alert one player claimed their character was being. The party and the monsters each operate as a cohesive unit.

In this reading, the Thief messes with that cohesion. The Thief’s real special ability, and the way it affects the systems in place, is through the ability to act independently in specific ways. If normally, you have a 33.33% chance of surprising a group of enemies, no matter what, adding an additional and separate 20% chance to get the drop on them, observe them, etc. is actually really awesome. By being able to individually attempt this, the Thief adds another tool to the party’s arsenal, the same way a Wizard adds another sleep spell, and another Fighter adds an armor class of 2 that you can stick in front of everyone else.  This reading is very gamey and systems-focused, but I’d argue that B/X as written is a really systems-heavy game.


Picking locks, is I think another one of those situations where time is the main factor. I’d let a player roll to do those once per exploration turn, eating up light and encounter rolls. If you read this a 15% chance to pick any given lock in under ten minutes, as opposed to finding the key somewhere in the dungeon, or bashing the door down and making a ton of noise, it’s actually pretty impressive.

Picking pockets I’m less sure about, but I’m also not sure how often it’d come up in the assumed B/X context of crawling through dungeons and encountering groups of baddies. It’s also inherently a super risky action. I’m fine with that as-is.


Find or Remove Traps is a weird one, mostly because it’s broadly defined, and because of that annoying Find” stuck on the front. To understand why, we need math!

Any PC has a 1-in-6 chance of finding something when they spend a turn searching an area, that is if there is anything to find. That’s about 16%. Which means a level 1 thief, at 10%, has a worse chance than anyone else at specifically finding traps? It just doesn’t make a lot of sense. In my original reading, I figured that the Thief could use the 1-in-6 for finding traps until level 3, when they could then roll on their percentages. Then I actually looked at Supplement I: Greyhawk, and like a pressure plate on the floor of a crumbling temple erected to thirsting gods, it all clicked.

In Greyhawk, the first public appearance of the Thief, no mention of finding traps is made when the thief skills are described. Instead, the ability is described as remove small trap devices (such as poisoned needles).”

Interestingly, no mention of searching is made, only removal. The emphasis on small traps, like the poisoned needles and the like, sets this skill apart from the ability of any character to spend a turn generally searching an area. For one reason or another, this specification was removed by the time B/X came around.

It’s still a little vague but here’s how I’m going to run it at the table:

  • Everyone, thieves included, searches normally, 1-in-6 for generally looking over an area or finding secret doors.
  • When specifically checking for a small, mechanical or tinkery trap (poison needles, not trap doors), thieves may use their Find / Remove traps skill to search, if it is better than 1-in-6.
  • The Find/Remove traps skill then operates similarly to picking locks. the percentage chance is the likelihood that a thief can disarm the trap within a single ten-minute turn.
  • Larger traps, less reliant on specific tinkering and mechanical know-how, should be circumvented with description.

I think this reading ties the find/remove traps skill more thoroughly into the existing system of turns and resources, and delineates a specific type of trap that thieves are skilled at removing. These little traps are far more similar to picking locks than anything else, in that they can’t really be dealt with through player description. Much as with sneaking, I’d probably rule that without some clever workaround, this mechanical know-how, and the ability to harmlessly remove these traps, isn’t available to other characters.

Some Alternatives

My goal with Thursdays in Thracia is to run B/X as close to the original intent as possible, so that’s what I’m going for with this reading of the Thief. Many gamers, however, use old school D&D rules as a basis for their own game, and hack or change the rules extensively to get exactly the feel they want. Still others have come to different conclusions about the original rules. Here are some of the alternatives I find most interesting or workable:

Robert Fisher presents a good method for using the existing tables and mechanics to handle other classes sneaking around, searching for traps, etc.

Dyson Logos has a couple different systems, including a 2d6 system that allows for some customization and inclusion of ability score modifiers.

In White Box Fantastic Medieval Adventure Game, Charlie Mason presents a cool take on the Thief, using a general Thievery” skill rolled on a 1d6.

Lastly, for a more radical departure, The B/X Rogue, by Gavin Norman, presents a highly customizable take on the class, which should nonetheless slot easily into any old school D&D game. He accomplishes this by presenting a long list of talents” which the character either has or doesn’t have, and they choose additional talents as they gain levels.

How do you do thieves?

My interpretation here is just one possible way to look at the class that totally ruined D&D, and I’d love to read more. If your running an old-school game, post a comment below telling me how badly I’ve misunderstood the intent here and how you make them work.

May 28, 2018