Larp tricks: simulating Holmes-ian deduction in games

Via Facebook, a pointer to an article on “The New Detective System of “Os Loucos de Lisboa””, which has an interesting mechanical innovation: crime scenes littered with coded cards for clues.

Detective scenarios use clues. Those clues are represented by cards, which can be folded in two: in the front they have a symbol (more on that later) and a description of the clue (what the character is supposed to be seeing or thinking about); in the back they have an index (a number from 0 to infinity) which identifies the clue; inside, they have a set of hypotheses.

For instance in a murder scenario, players could see a clue card which would say “fingerprint” in the front, and “#25″ in the back. Inside it could have the following hypotheses: “the fingerprint is from the murderer’s hand” and “the fingerprint is not from the murderer’s hand”.


What makes this system great, however is the interaction between clues.
That’s acheived with index-based hypotheses. Index-based hypotheses follow this format: #index -> letter. For instance: #65 -> C. In this case, “#65 -> C” means that the C (third) hypothesis of clue “#65″, whatever it is, is true.

So you can have clues that tell you that other clues are true, without telling you what they are if you haven’t found them (also letting the characters have those “we’re missing something…” conversations you see in TV shows). The down-side though is that you need to have your web of clues meticulously pre-planned beforehand - and if the characters miss one, the whole thing could fall apart (so: make the clue cards very obvious by colour-coding, so they don’t have to pixel-bitch).

While the method is focused on crime stories, you could use it for any investigative story, such as occult or scientific investigations, allowing you to have a genuine sense of unravelling mystery in games. For bulk information, you could use computer support (so have the card contain a password to a file). Or, if you want people to spend some time “processing” the clue, or give information to some people but not others, you can use simple encryption (e.g. clues of a certain type are Caesar ciphered, with the relevant character knowing the key).

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That is an interesting idea. Would be keen to see someone have a go at it in NZ. Seems to me like it’s probably something that you would want to implement more for a longer game, to really let people get the full benefit of it. Three hours for the whole game probably wouldn’t really allow for much depth to the clue system.

I imagine if a game writer wanted to take it further, they could also have suspects to be interviewed by the players. Also, perhaps, if the game is set in relatively modern times, there could be a ‘foresensics lab’ or similar run by an NPC, where players drop some clues off at, and come back a while later to get more information. I mean, the players could do the forensics themselves, but I imagine most people wouldn’t be terribly interested in pretending to peer through a microscope or do some sort of painstaking computer analysis themselves.

I suppose it would also kinda depend on how much the writers/GMs would want to go in phys-repping clues. For example, if the GMs know in advance who will be playing the murderer, they could maybe create a clue card with a real picture of that person’s partial fingerprint on it (with their knowledge and permission of course), so when someone busts out their fingerprinting kit they bought for the game, they can try to match fingerprints for real.

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Yes - simply thinking about it in terms of how many clues you can collect, three hours doesn’t give much time. But it might be able to be used in a short Christie-style murder mystery. You could however have real fun with it in a day- or weekend-long scenario.

This seems really clever; for the example card (“Fingerprint”); how would some characters now which hypothesis is the correct one?

A later card, it sounds like. But introducing the hypotheses can also be a useful prompt for the characters - something to talk about. (“Someone left a fresh fingerprint. Which means either the killer didn’t wear gloves, or there was someone else here. No other body, so clearly not a professional hit”).

Thinking about it, I think a system like this would fit in perfectly to a Nightmare Circle/Witch House style game, which of course already like to involve some investigatory elements. The occult elements would just expand the sort of mysteries (and therefore clues) that can be created.

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