Rolling Dice in Call of Cthulhu

Generally speaking, I dislike binary pass/fail mechanics in games. Mixed success or success at a cost drives stories in much more interesting directions. Sometimes you want outright success to wrap things up, but most of the time progress is enough and the cost creates interesting decisions and dilemmas.

Investigators don't always sleep easy.
Call of Cthulhu Keeper Rulebook p. 185 (c) 2015 Chaosium Inc.

Surprisingly for such a staid, traditional game, Call of Cthulhu has excellent advice on this that really reflects how I like to run games.

In the current edition (7e) of the Keepers Rulebook, Chapter 10 covers “Playing the Game”. Yes, yes, they wait all the way until halfway through the book, but that’s because this is a bit of a grab bag of advice for the Keeper (GM). And on page 194, the section “Rolling Dice” gets into the meat of what bothers me so much in some play cultures.

Dice Rule 1: The Keeper decides when to call for a skill roll.

I like to skip a LOT of rolls (usually in the players’ favor). If there’s no interesting stakes to their action, why not just let them succeed? This isn’t a resource management game where they need to consider how much weight they’re carrying and how many spell slots they have left. Most of the game consists of the players asking good questions and drawing correct conclusions. When I run games, we roll dice far less often than with many other GMs – and Call of Cthulhu officially says this is fine (it’s also fine if a Keeper wants more rolls, of course!)

Dice Rule 2: Dice don’t tell stories; people do.

This little bit has what I think is perhaps the single most important sentence in describing what dice do in my games:

When a player wins a skill roll, his or her goal is achieved (as agreed before the roll), but when they lose, the Keeper decides what happens.

The next couple of rules emphasize this further, so I’ll cite them before digging in.

Dice Rule 3: Losing a roll doesn’t necessarily mean failing the goal.

Put these two together, and suddenly you see that the game is not actually pass/fail. Yes, there’s a “pass” outcome (which is usually low probability). But if the player loses the roll, the Keeper decides what happens next. This lets us ensure the story keeps moving: the game doesn’t actually mean a failed roll means missing a key clue that moves the game forward, and in fact says:

Problems can arise if you declare an outcome that blocks play.

If they need something to happen or the game just grinds to a halt (which usually reflects a problem with scenario design, but that’s out of scope here), then that thing needs to happen. Losing the roll can mean other things.

Dice Rule 4: Dice are used to determine who tells the story.

This recalls the importance of what Dice Rule 2 covered. The book even gives an analogy:

One way to think of this is to compare it to a football game in which the two teams battle for possession of the ball. In Call of Cthulhu the player and keeper battle for “possession” of the story. The side that wins the dice roll gets to run with the metaphorical ball for a while.

That’s deceptively deep, I think. Blades in the Dark codifies this a bit with Position and Effect. The player says their goal and the Keeper decides to call for a roll; agreeing on the possible outcome if the player wins the roll is setting the Effect. A good Keeper should then give the player at least some sense of the stakes if the player loses the roll (the Position). We don’t have to tell them every particular hidden thing, obviously, but the general magnitude of the stakes should be known at a minimum. And taken with the previous rules, failure could mean they still get the information but opponents are alerted, or they find the danger and it’s worse than they expected.

I apply these same things to other games. In Mothership, a player missing a Skill Check doesn’t necessarily fail to do the task but just take stress, for example. When I play Into the Odd, a player making a save might have a significant enough advantage that we’re just checking to see whether their opponent gets a chance to respond.

Since I didn’t play Call of Cthulhu before 7e, I don’t know if this advice is new or not. But I do like seeing it in one of the most “trad” of trad RPGs. The book has more good advice, of course, and much of it is worth a read even if you’re not running this specific edition.

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