I've been rereading the basic rules before my first actual game (hopefully this week or next) and am a little confused on Opposed Checks. When do I call for one from one of my players? Just a couple of examples would be great.

Thanks!

p.43 : Opposed Dice Pool Example

When a PC is trying to sneak past a guard, roll PC Stealth vs guard's Observation.

When a guard is trying to sneak past a PC, roll PC Observation vs guard's Stealth.

When a PC is trying to convince a guard to let him through the watch cordon, you could roll PC Charm, or PC Guile, or PC Leadership, vs the guard's Discipline, depending on how he's trying to influence the guard.

When a PC is trying to take something out of the guard's pocket without him noticing, you could roll PC's Skulduggery vs the guard's Observation.

Basically any time the chances of success are directly affected by the ability of an antagonistic character.

In addition to the examples a number of others have sited, there are also several Action cards that use opposed rolls.

An example is the Twisting Words card which says "Guile (Fel) vs Target's Discipline (WP)".

Thanks guys for the answers, this sentence is really a rule of thumb I was looking for "Basically any time the chances of success are directly affected by the ability of an antagonistic character."

Also, you're going to have to forgive me, but I have a follow-up question. In the example of Twisting Words being Guile (fel) vs. Target's Discipline (WP), we resolve this just like a normal combat roll but WP is the defense value instead of a physical defense? And then instead of damage, the individual card lists the "damage" or general effect of a successful "attack", right? Don't know why this is hard for me to grasp, but it is.

there are three kinds of checks: standard, opposed, and competitive. Whenever a task is performed against a set challenge level it is called a standard check. all checks against "target defence" are standard checks with an easy (1d) challenge rating.

twisting words isn't vs target defence, it is vs target discipline which i take to mean it is an opposed check, your guile (Fel) vs their discipline (WP). target just clarifies whose discipline you are checking against. for example, devious maneuver is skulduggery vs. observation, not target observation because the target's (in this case your ally) observation is not important, only the highest observation amongst enemies in the encounter matters and the card gives you a little note to let you know.

lets say we have a rogue with 5 fellowship who wants to embarass some peasant in a bar with 2 willpower, in an opposed check the dice pool for the action (with no stance dice and no skill training or extra modifiers for either party) would be 5 characteristic dice because the peasant's willpower is less than half of the rogue's fellowship. he would have to roll a bunch of blanks and boons to not succeed. even if you just roll boons you stress the dude out. is this reasonable? i think so, peasant's suck. let's say our rogue tries to humiliate a rogue of equal fellowship. he would roll 5 characteristic and 2 challenge dice. still pretty reasonable.

ultimately, gms get to choose if they want to make a standard check an opposed check and they also get to decide what the challenge rating for a standard check should be. you could kind of think of an opposed check as a standard check with a less arbitrary challenge rating. it just seems that the designers intended people to hit each other almost every time in combat so that combat will go faster and so they set the challenge at easy as a shortcut. if you feel like you want your party to know they suck just raise the pc's challenge rating to hard but keep the npcs at easy or simple. it is a really flexible system.

i think you just got stuck in 4ed DND logic where attacks all target different attribute derived defenses: ac, fortitude, reflex and will. in wfrp defence just means armor and shield (passive) or parry, dodge, block (active).