The more I run the game, the more I realize the importance and simplicity of a 1 in 6 chance. Flipping needless through your unorganized GM binder trying to find rules, stats, or gigantic tables of possibility is just a giant waste of time. No one wants to sit there while you desperately try to figure out what's happening.
Not only do I use this technique for surprise, but for morale and reaction checks, too. Its just so straight forward, and the best thing is it keeps the game running. A few examples of how this works...
Let's say the players bust a door down and stumble into a room. There's an Orc at the other end stirring a pot of something foul. I roll a d6. If a one pops up, he is surprised, regardless of the ruckus because it appears he's deaf! Any other number comes up and the Orc hears them, turning around with weapon in hand!
Alrighty, lets say the heroes are fighting a group of goblins and the goblins are outnumbered, they keep getting killed off. Roll the d6. If a 1 comes up, the goblins decide they are going to make a stand and fight to the death. Anything else comes up, they flee in terror. On the other hand, for say a fairly tough high HD monster, he may only flee on a 1.
Reaction Checks & Roleplaying
Let's say the fighter in the party is trying to get a really good deal on armor from the local blacksmith. We roleplay back and forth bartering.
Blacksmith: "I can't possibly do it for that price".
Fighter: "Come on, I plan to bring you more business"
Roll a d6, 1 comes up the blacksmith agrees to do it on the cheap. Anything else and he flat-out refuses to do it for that price or tells the fighter to leave his store, he's insulted! I will do the same thing in most bartering type situations.
Here's another example of reaction in a combat situation. Let's say the PCs and some monsters meet up in a room together. On a roll of 1, I might decide that the monsters don't want anything to do with these guys and make a break for it. Alternatively, I'll decide that the monsters will try and talk their way out of the situation.
Another reaction that comes up quite a lot is the "meeting a stranger" in a tavern. We may roleplay the bar scene, heroes having a few drinks, regaling the locals with large tales of adventure! They meet up with a lady wearing a dark hood. She asks to speak with them privately. The heroes follow. She discuss her need for some adventuring types to help fulfill a promise she made to her dying father. She then questions the PCs on their credentials. Roll a d6. A 1 comes up and she decides that the PC's stories are unbelievable or paint them as nothing more noble than "murder-hobos". She gets up to leave. And now the PCs must persuade her to give them a chance.
Keeping all this in mind, sometimes the less the dice rolling the better. I prefer to give the players a chance to roleplay out a situation. Using that possible 1 in 6 chance as my guide.
When in doubt, do what countless GMs have done over the years: roll that D6!
Authored by Shane Ward