For a sourcebook (which never got printed), I created a short and easy system for roleplaying a the solving of mystery. In a nutshell, player characters investigate the mystery. Through roleplaying, they collect clues. As the author of the mystery, I already have several clues planned, but this system should also fit well into an improvisational style of play. When the PCs discover a predetermined number of clues -- pow, the mystery is solved or at least enough of it to proceed to Act II.

The player characters are free to pursue their own investigation however they
wish. There is no specific chain of scenes that the players must pass through to solve this
case. The game master probably shouldn’t rely upon the players to strictly solve case
through deductive reasoning. A player shouldn’t have to be a great detective in order to
roleplay a great detective. Furthermore, simply revealing the solution through a single
psychic vision or magic spell could be too easy and unfulfilling for the players. Instead, here is a suggested system. The game master can count the total number of clues which the player characters gather. When the player characters gather enough clues, they may proceed to the next part of the mystery.

Each clue is described by what it is and how it might be discovered. There is also a suggestion accompanying each clue about what skill rolls, deduction rolls, or Perception Rolls are needed to apply each clue toward solving the mystery. The “Role Required” entry is
optional. The game will be much more challenging if the rolls are needed. When the
player characters have gathered and applied three or more clues, they are one step closer
to solving the case. When successful, they may proceed to the climactic confrontation
with the killer.

There are several aspects that your 'counted' clues could  be helpful.

One, as you mentioned, you could have a upon achieving a certain number of clues, the story moves on by action of the antagonist fearing they have been discovered, or by the GM revealing key information to the players allowing them to move the story forward against the antagonist.

Other options could be, after collecting a certain number of clues, they may be able to 'spend' clues to gain a hint leading them to some of the remaining clues.

Another option could be that based on the number of clues gathered, they may get some sort of a bonus in the final battle.  It could give them a bonus in the initiative check, or if they had collected a certain number of clues... they end up spoiling the villains' 'surprise round' attack as they figure it out as they reveal themselves, rather than afterwards.

I somewhat like the idea of being able to use skill checks to 'cash' in clues.  Although there might still be some overall benefit for having gotten a clue, even if the skill check was failed.  It would keep the random factor from being completely in control, but would still give you a chance for a reward of some sort.  [could be some environmental adjustment to the coming combat, or could be a monetary or XP bonus, or certain clues might grant a boon like, allowing a player to reroll a future save/to hit or such, or might grant them the ability to force a villain to reroll something?]  Something that allows that fluff to have a crunch effect later in the story as it affects the random factors of the games then.

Is this the sort of feedback you were looking for?  I wasn't completely sure what feedback you were looking for.

Sounds like a good system to me. Expecting players to engage in deductive reasoning is a pretty tall order unless you happen to have a really good group who also happen to have no RL distractions to take their eye off the ball and your game progresses quickly enough for the players to recall what happened in the last scene.

Clue counting enables the GM to offer a conclusion (maybe via a NPC) whose accuracy may depend on the characters' deduction skills. I'd be interested to hear more of the mechanics, unless you're still intending to sell a publication.

This is a really good idea. I think I will modify it for the horror game idea I have in mind. Basically the way I'll run it is I set up the prelude as a sort of exposition of what the story is about, maybe have players make up some introductory posts to transition into actually going into the area.

Then the clues they pick up (through carefully written examination posts, rather than use of the perception stat, since I don't plan on having one.) will gradually discuss what the danger actually is, and transition to how to defeat it. If the players find all the clues, they have an edge. If they don't, they can always guess based on their character's knowledge of horror.

I kinda like the idea, but I'm not sure how it would function in actual play.

So say that there have been a murder commited by an unknown person, and by collecting clues, the players will figure out where the murderer is hiding out. We'll just say they need to collect three clues.

Can they find the hideout by finding the murder weapon, fingerprints and a recipt left by the murderer? Or will the clues have to be clues specifically towards where the murderer is hiding out? What if the players figure out where the murderer is after collecting the first clue? Will they be prohibited from acting on that knowledge until they've found two more?

My take on it is that ideally it's a little of all of the above. Not directly where the murderer is hiding hopefully, but depending on the type of game, things can hinder progress. perhaps enough clues need to be gathered for the case to stand up in court. I know in the Horror game I want to run, players will know there's a house on the other side of the lake from them, and they may immediately assume that taking the direct path there will be the easiest.

The circumstances regarding my particular use of this system are more along the lines of: There are enough assumptions pre-loaded into the scenario that the players will make the wrong one if they don't pick up clues to mitigate that.

The OP seemed to be describing a game that would be littered with clues, so those clues may be of different types - identity clues, hideout clues, motive clues, next victim clues, etc. The GM might look at which clues you collected and use that information to decide which scene to unfold next.

Another option could be graduated clues - the GM gives you a clue and you try to resolve it. If you're struggling, you PM the GM and s/he gives you either a hint or, ultimately, the 'answer from the back of the book' so you know exactly what the clue is supposed to tell you.

I appreciate all of the analysis and discussion.

Here is how I was originally thinking that it would work. When I plot out a mystery scenario, I have a few specific scenes in mind. In a game of Beyond the Supernatural that I am currently running on another site, the players are investigating the murders of a serial killer. When they collect five clues -- any five clues -- they will trigger the revelation scene in which they locate the killer's hideout. The killer is working for a second villain. When they collect an additional three clues, they gain access to the big boss fight scene against that second villain.

It is a system which strains credulity, I admit. The clues that they collect might not make any real-world sense as a logical argument. That is kind of the point. I am attempting to replace the restraints of a real-world logic with a rule mechanic.

It's sort of like how in one of the Star Trek RPGs, the techno-babble rule would allow characters to make a dice roll and if successful solve their immediate problem with a techno-babble solution. Rules like this actually some gamers (myself included), but they are necessary for running a smooth game within genre conceits.

I think with this idea I could emulate Until Dawn's "totems" and literally be emulating (but with a different flavor) the technobabble you just mentioned. Handwavium is weird to me too, but I think for some things I could embrace it. I'm running my idea in phases, and I like the idea of phase checkpoints to determine when the next phase starts... and like you said, even going so far as to blatantly give a revelation.
This message was last edited by the player at 20:21, Fri 09 Oct 2015.

In reply to steelsmiter (msg # 9):

Please let me know how that works out for you.

It may be a bit, I'm actually doing a new system, because I don't like how a lot of horror games these days turn into shoot em ups. I'll throw it up when I get ready to playtest.