Clues can be described using at least two different axes: obvious/hidden and known/unknown. I'd vaguely hinted at the first in the previous post on traps, but now I'd like to break down "hidden" a little further:
- Obvious: anyone under standard conditions will notice the clue.
- Covered/Concealed: only those who bypass the cover notice the clue.
- Secret: only those who examine the target in the proper way notice the clue.
- Obscure: a combo of Concealed and Secret.
On the other hand, Concealed clues have something physically blocking one of the senses, which is why I also referred to it as "Covered". This is a trap door under a rug, a chest under a bed, a niche behind a curtain, or even a door behind a pillar. Removing the cover (or, in the case of the pillar, changing position) changes the clue from Covered to Obvious. Explorers get these clues if they perform an action that would uncover/discover the clue. Such actions are generally pretty simple, but the players must state they are "looking in, under or behind everything," at the very least, or the clue will be missed.
Secret clues will not be casually revealed. A Concealed clue might be concealed by accident, but a Secret clue was deliberately hidden. If the correct location is searched, the explorers might get lucky (this is the rationale behind rolls for secret doors.) If the explorers take an appropriate action, the Secret clue becomes Concealed, rather than Obvious; for example, if the characters search for secret doors by holding a candle near the wall and moving it around slowly, they might spot a gust of air from a crack, but they do not automatically know if this is a secret door or something else., nor do they know how to open the door. It might take a very simple action (push on the edge to make the section of wall rotate.)
If the action isn't simple, the clue is Obscure rather than Secret: the action that must be performed is not obvious even after the secret has been revealed. It is essentially a chain of clues.
The Known/Unknown axis of description is roughly equivalent to the Obvious/Hidden axis:
- Common knowledge: known to all ordinary people.
- Uncommon (or Expert) knowledge: known to people with an appropriate background or training.
- Private knowledge: known only to those involved or those they have told.
- Lost knowledge: previously known, but there are no surviving experts or people privy to the knowledge.
- Unknown: Lost knowledge should cover this, but for those who need it, we can just consider something as totally new, requiring research.
Most of the time, we don't need these labels, because most knowledge is Common or at the very least known to a fairly obvious group of experts. Similarly, there are a lot of Obvious details which we don't need to label "Obvious" or even record at all; part of the GM's job is to act as a referee, deciding if there is any Obvious Common clues relevant and making stuff up as appropriate. We only need these labels when describing exceptions to the norm, so that we can classify them into broad types.
Next up will be an application of this to hazards, traps, and tricks.