• What must happen, happens. If the adventure simply cannot go forward without a PC spotting the shadowy figure darting around a corner, I only pretend to roll. Or else I call for open rolls from everyone, and announce the info to whoever rolls highest or lowest, no matter what the result.

• Very little is truly crucial, though. Most of the time there’s more than one way to wisdom, and quite often I let them miss a clue if I think they can work around that bit of ignorance, especially if they will later berate themselves for missing it.

• Pleasant but not vital rewards, like hidden treasures, are sometimes just missed. Let the dice fall where they may. It’s a chancy world.

WHAT TO ROLL
There are four ways I’ve found to make notice checks within the retro rules. In three of these methods, I call on the players to roll their own dice.

Surprise Checks work for any situation where the PCs may not realize what’s happening in time to react. I let the player of each PC who might be able to respond roll a d6. Instead of saying, “Roll to see if you are surprised,” I just say, “Roll a d6 and try to roll high.” On a 1 or 2, that character fails to react appropriately for a round while circumstances move forward. Thus Surprise Checks give each character a 2 in 3 chance to notice what’s going down: good odds. Recently I used this mechanism to determine if a PC realized that the dark shape assaulting him in his room was an amorous barmaid who’d been waiting up for him. Since he was surprised, he didn’t know who it was, and might have responded with deadly force. In other words, the roll was not to be “combat ready,” but to clearly grasp the situation in a very quick time and not make a blunder in ignorance.

Intelligence Checks represent the chance that a character understands the significance of something that’s right before his eyes. Players make their own d20 rolls, attempting to get the character’s INT or less. For example, I’d call for INT checks from everyone to realize that the black marks on a stone wall look like signs of a big fire in the recent past. If no one succeeds, I’ll pass over those marks very quickly in description, allowing only a highly attentive player the chance to go back and ask about them even if his dice failed him. Sometimes only a single character gets an INT check; perhaps his partners are not paying attention, or not close enough, or lack the requisite background knowledge. For example, a spellcaster studying some runes gets a check, but not so the fighter reading over her shoulder. Any PC fiddling with a small object in his hands gets a solo check; others must take their own turns with it. Overall, INT checks give about even odds to notice something, but naturally higher for some characters than others.

Hear Noise Checks, as written, apply only to active attempts to listen, but I’ve come to use them as a general measure of sharp senses. I use Hear Noise whenever a subtle sensory detail might just pass the party by. Like Surprise Checks, the players roll their own d6s, but in this case I tell them to “Roll low.” Most PCs notice the detail only on a 1 in 6. Demi-humans pick it up on a 1 or 2, as do first-level thieves. Sometimes I allow Hear Noise for only certain characters, depending on who’s in a position to actually hear, see, smell, or otherwise note the detail. Hear Noise Checks, with their low odds of success, should not be used for sensations obvious to everyone, nor to interpret details. For example, if a breeze blows down a dungeon corridor, everyone feels the air move; INT Checks determine who realizes that it might be important. On the other hand, I’d call for Hear Noise Checks from everyone to note the faint smell of rotting flesh arising from a newly found stairway; if no one succeeds, I simply don’t mention that fact. If someone makes the roll, I announce the smell on the generous assumption that the PCs share information; in uncommonly divided parties, I would instead pass a note only to the sharp-nosed one. No Hear Noise result tells a PC whether the stink is likely to be zombies, uncured hides, or spoiled food; that’s a matter for player cleverness to determine unaided by the dice.

Secret Door Checks work very much like Hear Noise Checks, but only when a character carefully searches an area for hidden things. I run this one mostly by the book, but I apply it to anything hidden, from a lever disguised as a candlestick to a gold ring accidentally lost under a bureau. First I ask who is searching and who, if anyone, keeps watch. Then, assuming the necessary 10 game minutes pass uninterrupted, I roll a d6 behind the screen for each searcher.

ROLL YOUR OWN VS. SECRET DICE
I let players roll their own Hear Noise, Surprise, and INT and other characteristic checks, because it makes me laugh. There’s nothing the players can do if they fail, and it keeps them nervous, thinking they might have just missed a life-saving bit of info. On the other hand, for Secret Door Checks, as for skills like Hide in Shadows and Move Silently, players feel more nervous not knowing whether they have succeeded. That makes me laugh too, so I make those rolls out of sight. Besides, canny players might look at a set of failed Secret Door rolls and mentally mark the area for further investigation. A general failure to notice, on the other hand, suggests no out-of-character follow up. Players have no idea whether the mystery was a sign of imminent attack, an important answer to one of their nagging questions, or a mere odd resemblance between a statue and the current mayor, especially when the GM calls for such rolls frequently. Which I do.