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View Full Version : How well should the DM know the rules? [Discussion]



Wonton
2010-10-05, 02:47 PM
So, I'm bringing this up because last night's session was nearly a TPK against a couple of invisible enemies. All because our DM confused total cover with total concealment. When I asked him after the session as to why neither See Invisibility nor Glitterdust worked, he answered "Total concealment. It's as if there's a wall in the way."

[Moment of silence] :smallannoyed:

So, obviously, no one knows the rules perfectly. But at what point is it simply not acceptable to not know a rule? And does the DM have to know the rules better than the players? What's the best solution if it's the other way around?

Forged Fury
2010-10-05, 02:52 PM
Well, it generally is better for a DM to know the rules as well as or better than the players. Knowing the rules as well as the players helps to avoid situations like the one you listed. Knowing the rules better (and how they can be abused) helps to avoid the introduction of Pun-Pun into your campaign.

shiram
2010-10-05, 02:54 PM
When i DM and my players know a rule i dont, i either apply the rule if it doesnt screw with the plot, or i say the rule will be enforced hence-forth but not for the time being. Basically, i always try to keep things rolling.

I actually started Dm'ing because my DM's all we're tired of it, so they all know much more rules than i do, and its not an easy thing sometimes.

Greenish
2010-10-05, 02:56 PM
Knowing the rules better than the players isn't necessary, but a working knowledge on the basics is (ie. what sort of effects different conditions cause, how saves, bab, ECL etc. work). Of course, if the DM is new to the game (or even if they aren't), they can't be expected to know and remember everything.

Ichneumon
2010-10-05, 02:59 PM
It really depends on the type of game you're playing. If you're playing very "rule-light", like "you roll maybe 2 dice in an hour", than it really doesn't matter a lot. If your games are mostly hack-and-slash... well, it would matter more.

valadil
2010-10-05, 03:10 PM
The most important thing is that the DM know how well he knows the rules. He needs to be aware of what's probably just a guess and what's actually a memorized rules. Beyond that he should have a mental index of what rules appear in what books. Anything beyond that is unnecessary, but very helpful.

In a more competitive/antagonistic game I think the DM needs to know more rules. I've seen players run circles around new DMs and run the game into the ground. I wouldn't play in this type of game anymore, but for anyone who does, I think the DM should be as knowledgeable as the players, if not moreso.

mootoall
2010-10-05, 03:13 PM
Honestly, if a DM is using something, he should know how it works. If a player breaks out some obscure thing and the DM has to look up a rule, fine. If a DM doesn't know the capabilities of the monsters he's using ... well, he should learn them, or not use them.

valadil
2010-10-05, 03:15 PM
If a DM doesn't know the capabilities of the monsters he's using ... well, he should learn them, or not use them.

That's a good point. The GM has the luxury of knowing what's coming in advance most of the time. When he does he can look up any obscure rules before the session starts and memorize them or at least write down the page number.

Tyndmyr
2010-10-05, 03:27 PM
Honestly, if a DM is using something, he should know how it works. If a player breaks out some obscure thing and the DM has to look up a rule, fine. If a DM doesn't know the capabilities of the monsters he's using ... well, he should learn them, or not use them.

This. I use the same rules for the players. If you don't know what your spell does, then no, you can't cast it. Look it up before your turn or something.

It's your responsibility to know how your stuff works. This is true no matter who you are. It's also helpful to learn about how other stuff works, but it's not quite as critical.

Susano-wo
2010-10-05, 03:38 PM
IN general he/she should have a working knowledge of the most common rules, and make sure he knows what rules he/she is bringing into play.

But a GM can be cut come slack if he/she screws up, even badly. Only human, after all...Though perhaps a retcon would be in order with the current scenario. (not necessarily the whole scenario, just give the party back some HP, spells, etc to relect that they would not have had to spend as much to beat the baddies)

arrowhen
2010-10-05, 03:39 PM
When I DM, I *tell* players what rules I'm using. So if I make a mistake ("Yeah, that spell doesn't work because they have total concealment,"), it's easy for players to call me on it ("I think you're thinking cover") and I can fix it and move on.

Sleepingbear
2010-10-05, 03:41 PM
A DM should know the rules as well as they are able. What rules they do not know, they should know where to find them, how to interpret them and when to look for them.

DM's are human and are bound to make mistakes. Hopefully they are learned from and the DM improves.

That having been said, I've been in a game where the DM didn't know the rules, didn't look the rules up (and often didn't know where to look when they tried) and often grossly misinterpreted things. They had been DMing for years and apparently had made no progress in this regard. They were not receptive to constructive criticism or even being provided with page numbers for the rules. As the campaign had no other redeeming qualitites, I quit after three sessions.

Note that the issue in the above example was not the DM's knowledge of the rules but complete unwillingness to care about rules. I've been in games where the DM was new or didn't know the rules as well as I did but it's never diminished the games enjoyment for me.

So my recommendation is patience with the caveat that they need to be at least trying.

Morph Bark
2010-10-05, 04:04 PM
So, I'm bringing this up because last night's session was nearly a TPK against a couple of invisible enemies. All because our DM confused total cover with total concealment. When I asked him after the session as to why neither See Invisibility nor Glitterdust worked, he answered "Total concealment. It's as if there's a wall in the way."

[Moment of silence] :smallannoyed:

So, obviously, no one knows the rules perfectly. But at what point is it simply not acceptable to not know a rule? And does the DM have to know the rules better than the players? What's the best solution if it's the other way around?

How long has he been DMing? How long has he been playing at all?

Kurald Galain
2010-10-05, 04:09 PM
I find that the most important thing a DM should know is probability.

That is, before he asks for a DC 20 check, or three successes at difficulty 7, he should have a rough idea how likely the characters are to succeed at this. The gameplay gets silly really fast if the players breeze through checks the DM assumed were hard, or keeps failing against checks the DM thought were easy.

Encounters are a corollary of this: whenever using a monster, the DM should have a rough idea where it falls on the spectrum of "cakewalk" to "TPK".

Wonton
2010-10-05, 04:10 PM
How long has he been DMing? How long has he been playing at all?

He's been DM-ing on and off for 5 years now. He's never actually been a player (hard to find someone else willing to DM, I'd imagine).

grarrrg
2010-10-05, 04:13 PM
So, obviously, no one knows the rules perfectly. But at what point is it simply not acceptable to not know a rule? And does the DM have to know the rules better than the players? What's the best solution if it's the other way around?

A DM should a minimum of 12 INT and 14 WIS, with at least 8 ranks in Knowledge (DnDrules EditionX). A good CHA score wouldn't hurt either.

As for the second part, ideally, the DM should have the best rules knowledge, as they are the closest thing to a Judge or Referee.
In practice, having a DM who's willing to be corrected and learn will work too.

Siosilvar
2010-10-05, 04:19 PM
So, I'm bringing this up because last night's session was nearly a TPK against a couple of invisible enemies. All because our DM confused total cover with total concealment. When I asked him after the session as to why neither See Invisibility nor Glitterdust worked, he answered "Total concealment. It's as if there's a wall in the way."

[Moment of silence] :smallannoyed:

So, obviously, no one knows the rules perfectly. But at what point is it simply not acceptable to not know a rule? And does the DM have to know the rules better than the players? What's the best solution if it's the other way around?

Shouldn't the fact that those are specific counters to invisibility and nothing else have raised a warning bell in his head? See Invisibility does literally nothing else.

More on-topic, the DM should know the rules well enough to be able to run the session. If something comes up that he doesn't have the rules memorized for, he should figure it out as quickly as possible to continue play.

And, of course, if a DM makes a mistake, he should be willing to accept that he made the mistake, note that somehow, and move on. If he decides he likes it better the way it was played, that's fine, but add it to the list of houserules.

Morph Bark
2010-10-05, 04:22 PM
A DM should a minimum of 12 INT and 14 WIS, with at least 8 ranks in Knowledge (DnDrules EditionX). A good CHA score wouldn't hurt either.

As for the second part, ideally, the DM should have the best rules knowledge, as they are the closest thing to a Judge or Referee.
In practice, having a DM who's willing to be corrected and learn will work too.

Heh, under those rules I'd never be a DM in your group, and I've always been in mine and had few troubles. :smallamused:

I think it might be a good idea to have someone else in your group DM for a while, if he's okay with it. That way he gets to see things more from a player perspective and have more fun and less need to prepare, PLUS he gets to see how someone else handles these situations regarding rules questions.

AugustNights
2010-10-05, 04:30 PM
Story-telling is an art.
DMing, is a form of story telling.
It requires preparation and improvisation.
Any good Improviser or prepared performance artist will tell you that there are several rules to every craft. These rules should be well understood. Once they are understood they are no longer rules, but (cliche alert) guide lines.
Ergo a DM must know the rules well enough to skillfully break the rules, and have good reasons to do so.

Wonton
2010-10-05, 04:53 PM
Shouldn't the fact that those are specific counters to invisibility and nothing else have raised a warning bell in his head? See Invisibility does literally nothing else.

You'd think so...
Alright, enough ragging on my DM. He's quite good at 90% of his job, it's just the rules (and as a corollary of that, encounter design/balance) part that sometimes gets him. Unfortunately for both of us, the rules are my favourite part. I've always admitted I'd rather be in a crappy no-story hack-n-slash with great encounters than a beautiful moving epic where not a single d20 is rolled.


I find that the most important thing a DM should know is probability.

That is, before he asks for a DC 20 check, or three successes at difficulty 7, he should have a rough idea how likely the characters are to succeed at this. The gameplay gets silly really fast if the players breeze through checks the DM assumed were hard, or keeps failing against checks the DM thought were easy.

Encounters are a corollary of this: whenever using a monster, the DM should have a rough idea where it falls on the spectrum of "cakewalk" to "TPK".

Thank you. I feel that's definitely the most important part of DM-ing. Either calculating the probability exactly (i.e. "If I throw 8d6 fireballs (the average of which is 28) at my group, I shouldn't be surprised when I accidently roll a little above average and KO everyone but the fighter."), or just having that gut feeling/ability to judge quickly that allows you to eyeball how tough an encounter will be.

Ormur
2010-10-05, 07:10 PM
Speaking as a DM that doesn't know the rules as well as some of his players I think you should simply ask the players when you're in doubt and accept it when they call you out for a blatant misinterpretation as the in the opening post.

I once forgot you couldn't sneak attack in dim light because of concealment. I reacted appropriately. When there's a danger of a TPK I'd especially expect the DM to reconsider spurious rules interpretations.

I don't subscribe to that infallible DM theory. Of course if he hears out the arguments and comes to a decision that doesn't completely follow RAW I wouldn't blame him but such on the spot houseruling can quickly go wrong if it's done constantly and concerning things players might have changed their builds or tactics over.

AslanCross
2010-10-05, 07:12 PM
I generally know the rules better than my players, but when my players call me on the rules that can be settled by RAW, I defer to the book.

If it steps into RAI territory, the players defer to my interpretation.

Da Beast
2010-10-05, 07:37 PM
It really depends on the group and play style. On the rare occasion my friends and I break out our books I tend to arbitrate the rules regardless of who's DMing since I know them a lot better than anyone else. A group that mostly RPs with only a few dice rolls probably doesn't need the most knowledgeable DM either. A group that plays mostly hack-n-slash with players who don't mind getting one over the DM probably needs a very competent DM.

grarrrg
2010-10-05, 08:43 PM
Heh, under those rules I'd never be a DM in your group, and I've always been in mine and had few troubles. :smallamused:


Imaginary friends don't count as players :smalltongue::smallbiggrin:

ericgrau
2010-10-05, 08:48 PM
Enough to handle his own encounters. Excessive ad hocking of things that may TPK or otherwise give the PCs headaches when you make a mistake can lead to groaning. Ideally he should know enough to know the rules to handle the hair-brained schemes the PCs try to pull too, but I think that's asking too much.

onthetown
2010-10-05, 08:49 PM
Well enough that he should be able to run a session without running into the rules that he doesn't know. Don't know concealment rules? Don't use concealment-based sorts of monsters.

HunterOfJello
2010-10-05, 08:54 PM
DMs should do their best to know most of the rules well and always be able to look them up.

If they're going to feature a certain monster in a fight, they should look up all the relevant rules that they don't know by heart before the game.

Quietus
2010-10-05, 09:08 PM
In my opinion, it depends on the group. In the case of an inexperienced GM, as long as they're willing to admit the times that they're wrong, like in the OP, I'm okay with them having a generally low knowledge of the rules. With the caveat that they work to learn them, at least.

In groups like that, however, it's good to have someone on board that DOES know the rules, and is willing to help the GM out, even when it's to their detriment. Like in a recent game, where we were facing off against some crazy minotaurs to which the DM had added class levels - notably, Frenzied Berserker levels. I don't have the class memorized, but when the DM had the monster drop after running out of HP, I pointed out that somewhere through that class, they gain the ability to remain standing, regardless of how much damage they take. Thankfully, that ability comes in at level 4, and these only had 2 levels.. particularly since they had some rage variant that made it so their rages/frenzies/whatever didn't run out if there was opponents nearby. Never-ending rage that they couldn't die from? :smalleek:

It's all a balancing act, really. As a rule, though, low-rule-exposure GMs should try and have a "second" on hand to whom they can defer on rule debates, but they should be willing to learn the rules as they come up themselves.

Shenanigans
2010-10-06, 12:03 PM
I think the DM needs at least a decent working knowledge, and possibly at least another player who knows the rules well.

The problem comes when players know the rules better than the DM, know this, and abuse it. What's abuse? That's up for debate, but I'd generally say using obscure rules the DM clearly is not aware of (and not doing a courtesy check with the DM first), then being petulant when the DM disallows it on the fly.

Not that I speak from experience or anything. ;)

Tyndmyr
2010-10-06, 12:11 PM
I've always admitted I'd rather be in a crappy no-story hack-n-slash with great encounters than a beautiful moving epic where not a single d20 is rolled.

I would rather play the first one, yes.

Because the second one would be a book, and I'm capable of reading to myself now.

Curmudgeon
2010-10-06, 12:51 PM
Ideally, the DM should know all the rules perfectly. That's a goal rather than a requirement, of course. The DM should at least know where the relevant rules are, and be able to access them quickly if they need to refresh their memory.

It's OK for the DM to realize they need to look something up. It's not OK to be both unaware of the rules and to skip looking things up; that's a good way to make players who do know those particular rules really hate you. I've seen a DM screw over a player whose character was purpose-built to be a grappler by just "winging it" when it came to the grappling rules and thereby make their character ineffective. (The DM decided that all grappling was a matter of DEX rather than STR, and inverted the size adjustment under the justification that "the bigger they are, the harder they fall".)

Tengu_temp
2010-10-06, 12:55 PM
A DM should have a good grasp of the rules, know when he should look something up in the books, and know when to admit a mistake. If the players got screwed because the DM misinterpreted a rule to their disadvantage and someone points it out, a good DM will agree to retcon. "I said it, so it happened, even if I was wrong" is just a sign of being stubborn.


A DM should a minimum of 12 INT and 14 WIS, with at least 8 ranks in Knowledge (DnDrules EditionX). A good CHA score wouldn't hurt either.


Since when you need to know DND rules to DM any RPG? And 8 ranks means level 5 - rather high requirements in a world where most adults are around level 3.

big teej
2010-10-06, 01:11 PM
as a DM for a group that is (almost) entirely learning from scratch, I DO have the most rules knowledge, and I do my absolute best to run what I know, and be competant

if something comes up that I DON'T know, and I can't find the rules for quickly I typically tell the player "here's how we'll do it now, and I will find that before next session" or something similar

as a player, my stance on it is that the GM/DM/whatever should know all the major mechanics that inevitably come up during gameplay.

for example:
I had a player in my old group that wanted to run warhammer Dark Heresy, he had the rulebook, and wanted to run us in it, we all agreed to this.
we all took a quick look through what the classes do and what they're capable of and gave tentative commitments to what class
I picked "imperial guardsman"

so during creation, I bought a lasgun, and asked "what are the rules for auto-fire?" 'I don't know' was the response I was given*

*this is a short version, it was a much longer and uhm... 'heated' discussion than that....

but long story short, the GM eventually lost it with me asking about auto-fire and yelled at me for a bit :smallannoyed:

but I digress

if you volunteer to run a new system for your group, either be COMPLETELY OPEN about the fact you're learning too. or know the basic mechanics, implying that you know exactly what your doing, only to have that crash down as soon as a player asks a question, does not a fun game make.....

oh dear.... I ranted. :smallfrown:

El Dorado
2010-10-06, 01:12 PM
If the DM isn't as firmly grounded in the rules as he'd like to be, it can helpful if one of the players is designated as "rules guy". Of course, this works best depending on the trust level between DM and players. As long as the rules guy makes an effort to be objective, it can help while the DM gets up to speed.

Greenish
2010-10-06, 01:15 PM
Since when you need to know DND rules to DM any RPG? And 8 ranks means level 5 - rather high requirements in a world where most adults are around level 3.Not to mention that you'll need some spellcasting capability to be able to know about the rules of 10th edition D&D.

grarrrg
2010-10-06, 04:05 PM
Since when you need to know DND rules to DM any RPG?

Well, I'm pretty sure the OP was talking about DnD, and most other games 'technically' have a GM not a DM.


And 8 ranks means level 5 - rather high requirements in a world where most adults are around level 3.

You're terms are acceptable, requirements to DM (or GM) now stand at 5 ranks in Knowledge (XXXXX-game rules, edition##)

Friendly reminder, Knowledge (XXXXX-game rules, edition##) is a class skill for the following classes:
Real-Man
Brain
Loony < technically has the skill, but takes penalties the higher it gets
Munchkin < also has Knowledge (how to bork the game)

Thespian does not usually have Knowledge (XXXXX-game rules, edition##) as a class skill. But they can usually pick it up with one of their bonus feats.

Tengu_temp
2010-10-06, 05:32 PM
Well, I'm pretty sure the OP was talking about DnD, and most other games 'technically' have a GM not a DM.


Fair 'nuff. People assuming that all RPGs = DND is just my pet peeve.

Katana_Geldar
2010-10-06, 05:34 PM
It's not just knowing the rules, but knowing the ways the rules work in order to make something on the fly that either the rules don't cover well or don't cover at all. Particularly if players think of creative solutions to problems that are technically outside the rules, but reasonably permissable.

Problem is, having these in your head means there may not be enough room for obscure rules that are pertinent to a particular character or game. That means there's some pre-game work in order for the GM/DM/HM to learn these new rules that will be in use...or ask the player to learn them and explain them BEFORE the game so there's clarification on how it works.

Of course, if you're playing Paranoia... :smallbiggrin:

Morph Bark
2010-10-06, 05:39 PM
Imaginary friends don't count as players :smalltongue::smallbiggrin:

Whatever floats your boat, berk. Just don't let them hear it. They'd find it offensive.


Fair 'nuff. People assuming that all RPGs = DND is just my pet peeve.

To be fair, while this board is/was firstly geared towards DnD players (considering how it was founded, the comic, etc.), the OP's question is very much applicable to other RPGs.

Zaydos
2010-10-06, 05:49 PM
Personally I try and know the rules the best in my group; it's a holdover from my early experiences DMing 3.0 (mixed with 3.5) where I had a total munchkin (and the first DM I had played 3rd edition under) who tried to claim, well lots of things. He could quote RAW diplomacy rules; always had 2 18s (he would wait to roll stats until someone else asked a question); and claim more than the maximum number of synergy bonuses to diplomacy at 1st level. He knew a fair bit of the rules; not all of them by far, but enough to normally DM, and enough to know half the stuff he claimed as a player wasn't true (since some of them he'd quoted the rule on as a DM before hand). He was even willing to check the book, if you could tell him the general place in the book that had the rule; some of the time, other times it was "no; I'm railroading you." Did let me have a tribble familiar.

In general, though, a basic understanding is all that's necessary; look up the rules about things you're going to use before hand; know if you don't know all the rules and be willing to check if you're wrong; and if there's a player you talk about behind your back for cheating quoting a rule from a book you don't have, and someone else says he's wrong about it, actually read the rule.

grarrrg
2010-10-06, 07:16 PM
Fair 'nuff. People assuming that all RPGs = DND is just my pet peeve.

I generally assume that if someone says DM they mean DnD, and GM is used for everything else (sometimes including DnD).

I think it has something to do with "Dungeon Master" being inapplicable to games without actual dungeons...

The Big Dice
2010-10-06, 09:49 PM
I generally assume that if someone says DM they mean DnD, and GM is used for everything else (sometimes including DnD).

I think it has something to do with "Dungeon Master" being inapplicable to games without actual dungeons...

I use GM for every game. But then I tend to think of little bald guys in red robes that gives cryptic clues that only make sense at the end of the episode as being the Dungeon Master.

As for how well a GM should know the rules, it really does depend. I'd say know your rules rather than know the rules. And never be too proud to admit you made a mistake, not be too stubborn to back down if you realise you did something wrong.

But then I'm also an admirer of John Wick's GM techniques, so that might explain a lot.

That said, I prefer that all rules discussion gets saved for after the session ends. I don't mind admitting if I handled a situation wrongly, but if no character died because of my mistake, there isn't going to be a retcon wither.

Chambers
2010-10-06, 09:57 PM
I don't like playing in a game when I know the rules better than the DM. It's not because I'm a rules lawyer - I think some rules need to be changed (hopefully for the better). But if the DM is getting some of the core rules* of the game wrong, I feel compelled to correct him. And I know it makes me look like a jerk, which I don't like.

So if it's a RL game I'll just bow out instead of constantly telling the DM he's doing things wrong. That's no fun for anyone.

*Rules such as not being able to attack different targets during a Full Attack action. Gah. I tried to argue with the DM about this, after the session, and he just wouldn't see it. *Facepalm* That's when I left the group, cus' it wasn't going to be worth anyone's time for me to keep playing with them.

The Big Dice
2010-10-06, 10:14 PM
I don't like playing in a game when I know the rules better than the DM. It's not because I'm a rules lawyer - I think some rules need to be changed (hopefully for the better). But if the DM is getting some of the core rules* of the game wrong, I feel compelled to correct him. And I know it makes me look like a jerk, which I don't like.
I'd treat a player like you as a resource when rules questions came up. If you know them better than me, you can save me having to look stuff up in books. Which in turn saves time and reduces the amount of time spent on metagame concerns.

Besides, almost every player knows the rules that their character operates under far, far better than their GM does. That's perfectly normal gaming in my experience.

Chambers
2010-10-06, 10:20 PM
I'd treat a player like you as a resource when rules questions came up. If you know them better than me, you can save me having to look stuff up in books. Which in turn saves time and reduces the amount of time spent on metagame concerns.

Besides, almost every player knows the rules that their character operates under far, far better than their GM does. That's perfectly normal gaming in my experience.

That would have worked great. Except in the case where this happened, the DM didn't really want to know how the rules actually worked. It was both of our faults, really. I came off a little strong the first couple times he did things weird, and as a result he became defensive. So I left before it got ugly, which was the wise decision because he's still in my circle of friends instead of having a grudge against me.

I mean, I've been playing 3rd edition since the PHB came out - when there was only the PHB, before they published the DMG and MM [Look at me, being all grognard about 3rd edition :smallsmile: ]. He'd played in one 3.5 campaign, under an inexperienced DM, for about 3 months. So I had a pretty big twitch reaction against some things.

Zaydos
2010-10-06, 10:26 PM
I'd treat a player like you as a resource when rules questions came up. If you know them better than me, you can save me having to look stuff up in books. Which in turn saves time and reduces the amount of time spent on metagame concerns.

Besides, almost every player knows the rules that their character operates under far, far better than their GM does. That's perfectly normal gaming in my experience.

My last IRL DM used me as a rules resource; sometimes because I had the PDF of the PHB on my laptop, but he did it when my laptop was dead too. The strange thing: he was a veteran of 4e for months/years. I had played 3 adventures under DMs who didn't know the rules before his game. By the end of the night I was the person asked about rules for weird stuff.

Satyrus
2010-10-06, 11:20 PM
I have almost always acted as the DM and when I started playing I was the only one with books or access to the rules so I grew accustomed to having a rough handle on them and just making stuff up a lot of the time. Now in my 7th year (:smalleek:) of DMing I've DMed groups where players knew the rules much better than me to the point of rules-lawyers in a few cases. Regardless, I finally have a firm grip on 3.5 (except psionics which I refuse to acknowledge :smallbiggrin:) and have come to the following conclusion.

The DM only needs to know the rules well enough for everybody to enjoy the game. I still routinely ignore rules for the purpose of entertainment or plot but when it counts in the middle of a battle and I am unsure of something I've rarely had any problems with asking the players about the rule.

The general rule of thumb above pushes me against power-gamers and obsessive rules-lawyers though.

averagejoe
2010-10-06, 11:35 PM
See, I don't necessarily see the OP's problem as one of the DM not knowing the rules, it was a matter of making too hard an encounter - perhaps unintentionally, but still. I could see perhaps pitting the PC's against invisible creatures that can't be found with see invisibility and so on, but I'd make sure to do so when the players have some way of dealing with it. Whenever I provide an encounter I typically try to be reasonably sure that it's possible to win, even though my player's solutions tend to be different from the ones I have in my head. So I don't see this so much as a rules problem as it is a problem of putting the PC's in a situation they had no reasonable chance of winning. It's not so much a matter of looking up the invisibility rules as it is a matter of not asking himself, "How is it possible for the PC's to get out of this situation?"

As far as how many rules a DM needs to know, I tend to think that more is better than less, but not always necessary. I typically DM for our group, and I try to know the rules as well as I can. Then again, most of the people I DnD with are people I've known since high school, and I don't think we'd lose a lot if I knew the rules less well. In fact, my friends will DM on occasion, and they hardly know the rules, but we always have a fun time. But, for example, if I was DMing for a group I didn't know and was meeting for the first time for the express purpose of playing an RPG, I'd expect a higher amount of rules knowledge from the DM. So it can depend on the situation too.

DarkEternal
2010-10-07, 02:54 AM
Rules should be a guide line, not something that must be enforced at all costs. I stretch the rules constantly in our games if the party has good ideas.

However, if I did something that might kill the entire party because I interpreted the rules wrong, I certainly allow the PC's to correct me and make the correct adjustments in the game.