Enchiridion of Elucidation - Advice and Guidance for Trail of Cthulhu Players

Oct 6, 2026

Enchiridion of Elucidation is a rules-advice pamphlet for using Investigative Abilities in Trail of Cthulhu. It explains three player-facing methods: obtaining Core Clues without pool costs, purchasing Non-Core Clues with pool points for context and motives, and requesting Benefits that deliver useful outcomes while respecting scenario constraints. It also clarifies how spending ability pool points affects story presence rather than raw ratings, and outlines how players obtain GUMSHOE clues by getting into scenes, using the right abilities, and declaring clue use to the Keeper.

LanguageEnglish

CategoryReligion & Spirituality

FormatPDF

Pages40

Reading Time1 h 41 min

AccessFree to download

Advice for Players

Explaining the Use of Investigative Abilities to Players

Encouraging Players Not To Hoard Ability Pool Points

How Players Obtain GUMSHOE Clues

Enchiridion of Elucidation Being a pamphlet of useful analysis, advice and additions to the Trail of Cthulhu ruleset.. TRAIL OF CTHULHU Enchiridion of Elucidation Credits Author: Tony Williams. Layout: Tony Williams based on the original Trail of Cthulhu layout by Jérôme Huguenin Based on Trail of Cthulhu written by Kenneth Hite, featuring the GUMSHOE system by Robin D. Laws and illustrated by Jérôme Huguenin. This document is published with special permission Pelgrane Press Ltd., and may be redistributed for non-commercial use, but not hosted other than at [pelgranepress.com](pelgranepress.com) © 2017 Pelgrane Press Ltd. All rights reserved. Trail of Cthulhu is published by arrangement with Chaosium, Inc. Trail of Cthulhu is a trademark of Pelgrane Press Ltd. Pelgrane Press Ltd. is co-owned by Simon Rogers and Cathriona Tobin. Advice for Players Explaining the Use of Investigative Abilities to Players 􀀁 Imagine watching the TV show CSI — the team go to a crime scene and find a chemical spill. They send a sample to the lab and it comes back with a report saying, "We don't know what it was." It's the end of the show, the credits roll…a pretty boring episode. In Trail of Cthulhu players have Investigative Abilities to prevent this roadblock from happening. There are three ways of using them; applying these ways to the above example: 1. When the players find the chemical spill, the first thing they can do is use the Investigative Ability Chemistry to find a clue and because it's, what GUMSHOE calls, a Core Clue, it doesn't cost any Chemistry pool points to obtain; the players just have to be in the right place and have the right ability (and not necessarily have any pool points remaining in that ability). They'll learn that there are two factories that make this stuff. Those are two important leads for the investigators to follow — one or both of which will allow the players to move forward in the adventure. Core Clues are always concerned with providing the players with further avenues to pursue their investigations. 2. If the players want more information about the chemical, that's called a Non-Core Clue. It doesn't tell them where or what to investigate next, but provides a better idea of what they're up against or hints at the reasons or motivations behind the mystery afoot. Non-Core Clues usually cost pool points to obtain (some require no pool points). So, in this example, if one of the players spends a pool point of Chemistry they'll find out what the chemical is used for (maybe making bombs or hallucinogenic drugs). For a further Chemistry pool point spend, they might get some information on previous cases involving these chemicals. For a pool point of Streetwise spent they might learn which local criminals habitually use it. In summary, the second use of Investigative Abilities is to buy Non-Core Clues by spending pool points. 3. The third way to use Investigative Abilities is called a Benefit. This doesn't give a lead or extra information, but something else useful. Benefit purchases are usually initiated by the players; a player describes what they would like to happen and offers to spend an amount of pool points in a relevant ability in exchange. The Keeper should, more often than not, grant the player’s request unless they deem it unrealistic in relation to the constraints of the scenario. Keepers can also propose Benefits that they can offer to the players for purchase if they so wish. In the example above, the players might spend a pool point of Chemistry to prove their credentials to get a job in one of the factories, or to know a chemist who works there who might be persuaded to snoop for them. Perhaps they could spend a pool point to be able to bulk order some of the chemical to do some testing on it and spend a further pool point to speed up the testing process if they're in a hurry. Keepers should give players something useful if they're spending pool points for a Benefit

FAQs

What are the three ways Investigative Abilities can be used in Trail of Cthulhu?

Players can obtain Core Clues, buy Non-Core Clues with pool points, and request Benefits in exchange for spending pool points in a relevant ability.

How do Core Clues and Non-Core Clues differ in cost and purpose?

Core Clues provide further avenues for investigation and do not cost Chemistry pool points to obtain. Non-Core Clues provide information about what the players face or hints about reasons and motivations and usually cost pool points.

How does spending ability pool points affect investigators’ performance?

Ability ratings remain unchanged even when pool points diminish, so investigators are not literally worse. Pool-point spending mainly controls the likelihood of success and standout story moments until the next pool point refresh.

Oct 6, 2026

Upload by Emma Wilson