Saturday, May 1, 2010

Wandering Monster Checks

I understand that one of the strengths of old school D&D is the ability to customize and house rule it. That being said I find it strange that in 1e, a game that goes into great detail on weapon characteristics, there isn't better guidance for a DM on something as pivotal as wandering monster checks.

Maybe I'm wrong, maybe it's there, but I went searching and couldn't find any frequency or probability of checks recommended.

This seems strange to me because the central premise of D&D seems to be resource management and exploration. And time only really matters if the more time spent in a dungeon the more likely it is you'll be encountering something dangerous.

I remember this from my childhood-- rolling up characters was explicit and easy, how to DM was murky and mysterious. When I came to S&W I had the same problem, no mention of how often or common wandering monsters in a default dungeon level should be.

I made up my own ruling where I rolled a d20 and a 1 meant an encounter. I don't remember how often I intended to make these rolls but in play it turned into whenever I thought of wandering monsters. That sounds arbitrary, but it tended to work well, because I remembered wandering monsters when 1) players were doing something kooky or noisy, like busting down doors, or 2) there was a long lull in action because the players were being indecisive. My most experienced player knew what I was rolling for and would often take the cue getting everyone moving again.

In that sense, wandering monster checks worked not just as a resource management obstacle, and not just a added threat to the underworld, but as a practical prod to keep things moving and fun.

But I was never sure about my ruling. Recently I was reading Holmes and low and behold, there is explicit mention. Then I thought that maybe 1e is so coy about it because it was something so clear in OD&D. Maybe, because it's explicit in The Underworld & Wilderness Adventures too. After scouring my various rule books, here's what I found on the subject:
  • OD&D: volume 3, pg 10, every turn, 1 in 6 chance
  • Holmes: pg 10, every 3 turns, 1 in 6 chance--with mention of encounter distance
  • Moldvay: pg B53, every 2 turns, 1 in 6 chance--with discussion of encounter distance and the fact that wandering monster frequency may increase in more dangerous areas of dungeons
  • AD&D: no mention?
  • Swords & Wizardry: White Box: no mention
  • Swords & Wizardry: Core: no mention
  • Labrynth Lord: pg 124, every 2 turns, 1 in 6 chance--with mention of encounter distance, wilderness encounters, and the possibility of making random encounters easier/harder than average
  • Osric: pg 135, every 3 turns, 1 in 6 chance (sort of buried in a section called Searching the Dungeon)
  • Basic Fantasy: pg 133, every 3 turns, 1 in 6 chance
So, first, it seems there is consistency here; wandering monster checks all have a ~17% chance and they happen every twenty to thirty minutes. Except for oe, which makes me wonder if people considered every turn too frequent.

I have to give props to Labrynth Lord here, it has the clearest explanation of the batch. I'm not sure why S&W drops the ball here. It's great to give DMs room to house rule, but something as game-changing as wandering monster frequency seems both important and difficult to guesstimate without experience.

My own house rule isn't too far off; if you estimate that on average I was giving a 5% chance every turn, it isn't too far off the ~17% every three turns. If anything it looks like I've been making wandering monsters a little too infrequent.

Update 5/2/10: I looked more closely at the 1e Players Handbook. It has a section on page 101 that always felt odd to me. It felt odd because it never seemed clear to me who the audience was. Was it experienced players? Was it DMs (the PHB did come out before the DMG, right?)? It doesn't seem like the audience is intended to be new players; why go into such esoterica as invisible movement or spend time defining tricks and traps in depth?

Anyway, on page 103 under its definition of "Encounters" we get this:
"At prescribed intervals, your DM will generate a random number to find if any meeting with a random monster occurs."
I also went and checked modules B1 and B2 because they have so much introductory advice for DMs:
  • B1: pg 8, every 2 turns, 1 in 6
  • B2: no mention
With B2 this seems strange, because you could almost play D&D with just that book: they give you the attack matrices, the saving throws and random encounter tables. You barely need the rule books. But they don't mention how often to check for random encounters.

Update 5/3/10: Okay, one last addition to this seemingly trivial subject. I did finally find mention of the frequency of "periodical checks" the DM is assumed to make in the first addition DMG.

On pg 98 embedded in the example of play:
"(Here, as about 3 turns have elapsed, the DM rolls a d6 to see if a ’wandering monster’ appears; the resulting 5 indicates none.)"
So, as you can see this is strong evidence of the accepted default being every 3 turns 1 in 6. But as a teen experiencing D&D for the first time through the 1e books you would have to infer that.

I'm thinking now, that there are several reasons something so pivotal to the dungeon exploration experience could be ignored:
  1. The AD&D DMG, while a font of ideas and interesting information, is a mess. They forgot.
  2. You could forget something like that because it was assumed you already knew. OD&D, Holmes, Moldvay, etc had already spelled it out.
  3. Being exact as clockwork with a wandering monster check is less important than using it to prod overcautious or noisy players.
  4. Some areas are more dangerous than others and DMs can adjust the rate for themselves.
I think now that number 3 is more true than number 4. How great a difference can you really make in wandering monster frequency and still have it be a random encounter, 60, 70 percent chance every few turns? I mean at some point you are saying: "go here and you will fight lizardmen."

The most mention wandering monsters get is involving parties that are too cautious and slow or too incautious and noisy. So, I think the frequency of wandering monsters is explicitly tied to making the dungeon felt as a dangerous underworld. But dang, why not say it in so many words!?

How about this for my random encounter house rules summation:
Every 3 turns roll 1d6. A result of 1 means the party encounters a wandering monster.

Roll on a table appropriate for the particular location and level to see which monster is encountered. These tables may be provided by a module or created by you.

Roll 1d6 and multiply by 10 to get encounter distance in feet-- how far away the wandering monster is when it appears on the "radar."

Roll 1d6 for the monster and 1d6 for the party. If either rolls a 1 it means they are surprised for one round and cannot act while the other can act normally.

Roll 2d6 for encounter reaction unless the monster is undead or a ravenous beast. The result will mean:

2 Hostile, attacks
3-5 Unfriendly, may attack
6-8 Neutral, uncertain, confused
9-11 Indifferent, uninterested
12 Friendly, helpful

Note: Random encounter checks are meant to keep the dungeon feeling dangerous and keep players moving. If you find interesting action or combat has led you to forget a check or two, that's fine. But also, you can vary the frequency of wandering monster checks if players are standing around indecisively, being very noisy, or if their location in the dungeon is especially dangerous.

Was that so hard?


  1. I could be wrong, but I believe Gygax purposefully left this information out of the DMG precisely because he wanted frequency to be variable and determined by the DM as appropriate to the dungeon (more Gygaxian naturalism?)... Although outdoor encounters at least on land are given precise chances (DMG p.47) . My only other evidence for this is in the early Gygax modules. In the Hommlett dungeon for example we find "Encounter occurs 1 in 12, check each turn" for the upper level. In the G series, you'll find 1 in 10 or 1 in 12 depending on the level.

    Personally I like this approach and to me it's the more free form rules-as-you-go style I've come to like about old school gaming. I use the 1 in 6 every few rounds if I'm on autopilot, but less or more depending. I'm a bit surprised that OD&D codified it like this, but not so much that Moldvay decided to dial it back a bit or include it at all.

    I wouldn't be surprised if someone points out the exact page where I'm wrong though. It sure wouldn't be the first time. :)

  2. Thanks. I didn't know that about Hommlet. That's kind of weird to make it a smaller chance but more often, so the total chance is higher. Gygax seemed to always be doing weird stuff with dice like that. Why not just make it 2 in 6? That would be ~33% vs. his ~25. so a little more, but so much easier to keep track of.

    Ah well. I got nothing against people doing it their own way, but everyone seems to think DMs are born fully formed :) As a kid I didn't know how common monsters should be. Heck, I don't know a lot of stuff now. And it's odd when you juxtapose it with the absolute precision of stuff that doesn't seem all that important to me like how many XP it takes to go up in level.

    I was kind of expecting someone to point out a page in the DMG too, but maybe it really isn't there? I looked in the 1e players handbook too, but couldn't find it. So . . . in Advanced D&D you know what type of harlot you'll run into, but you can't be sure how often, haha.

  3. I could be wrong, but I remember something about this in Monster Manual II's appendix. I'm sorry but I don't have that book with me actually, so I can't check by my own. Anyway, great blog! Sorry for lurking here to long without commenting due to my bad english ^^

  4. Hey, thanks for commenting! Great English. I checked MMII and it, like the first Monster Manual, goes to great length to tell you how common monsters are, but that is in comparison to other monsters. It's meant to help you build encounter tables. But it never tips you off to how often you should roll on those encounter tables.

    I'm thinking Bulette is right-- they assumed we all could pick appropriate levels of probabilities fo ourselves.

  5. I think that Bulette is pretty much on the money. From the beginning, back in the Olde Days, it was conventional wisdom amongst everyone I knew or played OD&D with that you built your own wandering monster tables, usually adding a few special surprises unique to your personal setting, the dungeon and/or the session. You also, as DM, adjusted the frequency as you saw fit, either setting a hard and fast ruling up front or just rolling whenever seemed appropriate such as when someone dropped a rock down a well-shaft or knocked over a large bit of statuary--anything that made lots of noise or drew attention to itself merited a roll for wandering critters. You also rolled for wandering monsters anytime the group got slowed down with arguments, bogged down in minutiae, or things just got boring. It was a way to pick up the pace, and get things back on track, or at least keep them from devolving into extended b*tch sessions. A little grumbling goes a long ways. And nothing gets players to start playing then when a DM rolls some dice and starts to chuckle. It works every time.

  6. re: Hommlett, I should correct that actually it was on the upper level that it was 1 in 12/turn and that the lower level or dungeon was 1 in 6/turn, but I think the point remains the same.

  7. I don't have a DMG handy - but didn't the sample dungeon have an example of the DM rolling for randoms?

  8. @Roger: You're right, that's what the quote in my update is from, page 98.

  9. In a dungeon environment, I roll it (1 in 6 chancce) every time the group turns a corner, or if they're wasting time or being loud.