This year at GenCon I had tickets to two Trail of Cthulhu games. I also played two Call of Cthulhu games. I enjoyed all four games and the contrast between them made me think a lot about game design and about how to present mysteries.
Trail of Cthulhu has a couple of design motivated decisions regarding how you find clues. Basically, if the clue is something that you need to advance the plot, and you have the relevant skill, you find it. No roll. You just find it.
There are more nuances for using skills to find more information and accomplish things, so this isn’t the only mechanic in the game. It is the mechanic that’s most relevant to how you investigate mysteries. The decision to handle evidence this way was described to me repeatedly as an attempt to avoid having to fudge rolls to “give it to you anyway” or risk the story running into a brick wall.
I realized while I was trying to describe the games to my friends that in the two CoC games I played at the con, exactly that situation happened repeatedly. The Keepers struggled to find plausible justifications to tell us things, or fudged rolls, or gave us all a chance to roll, raising the probability that someone in the group would succeed. It was often silly and frequently not convenient for the Keeper or good for the story.
In those games, two Keepers were fighting the system to run the kind of game they wanted to run and two were not. This suggests to me that the ToC solution is the right one, at least for those four games.
A few months ago I read Justin Alexander’s essay describing the Three Clue Rule. I really like this essay. It describes some of the issues that arise from the failure of clue finding in mysteries and offers a different strategy to cope. The fundamental premise is, Game Masters are too clever when they plan mysteries. We should be including many, many clues for the players to find, at least three for each revelation they need to make to move forward in solving the mystery. Players will miss or misinterpret some, but they will eventually get where they need to be. I like this idea and it’s helped me in my own games.
There’s one thing in the essay that I don’t agree with. He mentions that the ToC system (GUMSHOE) lets you apply skills to just get deductions and use mechanics to solve everything. Possibly the Keepers I played under were doing it wrong, but all three times that I’ve played all we got was clues. How we parlayed that into solving the mystery was up to us.
We didn’t apply Collect Evidence in ToC and get the killer’s name written on the wall in blood, we got something like a bizarre painting, a strange black feather, a crumpled paper bearing a telephone number, or maybe even an invitation to a “church” party the next day. ToC guarantees that you will find clues to move you forward in the plot. They don’t have to lead you to understanding or solving the mystery.
I actually saw a failure of the three clue rule in one of the ToC games that I played. The Keeper gave us plenty of clues that kept us moving and discovering new things. However, there was a crucial thing we needed to realize in order to end the game in a “win” state and we did not get three clues for that crucial insight until it was too late. We weren’t screwing around. We were trying to stop bad things from happening. We just didn’t have the information we needed, so we did the wrong things.
ToC mechanics didn’t protect us from that failure. The Keeper is still the one who needs to have insight about which clues to provide to the players so they have a chance to solve the mystery.