D&D 5E How does Surprise work in 5e?

[Hriston]

I would say the PCs are Surprized by the trolls only and if the goblins attack at the same time as the trolls then that ruins the surprise. So the goblins would have to sit out the first round to avoid giving the surprise away.

But in the first example the goblins don't know about the trolls until they jump out. Would you say that the goblins are not surprised because the adventurers gave it away? The trolls in my first example are a third party, why shouldn't they be allowed to surprise the entire group of goblins plus adventurers? By the same token, wouldn't the goblins knowledge of the presence of the trolls in the second example negate the possibility of their being surprised, but not that of the adventurers?

I believe that what many here are proposing is a house rule that states that a noticed threat precludes the possibility of surprise, but for me that places a huge limitation on the conditions under which surprise can happen.

sorry about the edits.

 

[pemerton]

threat n. a person or thing likely to cause damage or danger

"Danger" is a relative notion. So is "likely to cause damage".

To give an extreme example, if an army is about to attack another army, a child with a kitchen knife suddenly sprining out from behind a tree is not a threat.

Interpreting what counts as a threat strikes me as a sensible, rather than ad hoc, application of "rulings not rules".

Whereas the scope ambiguity in "a threat" - does it mean "fails to notice at least one threat" or "fails to notice all of the threats"? - strikes me as a silly place for "rulings not rules". It's just bad drafting.

 

[Thunderfoot]

Ummm, the monsters jump out from behind stuff and the characters wet themselves?

 

[Azrothan]

The trolls in my first example are a third party, why shouldn't they be allowed to surprise the entire group of goblins plus adventurers?

Because they're already alert from having noticed a threat (each other)?
Edit: I'll have to dig into the rules about a third side in this encounter, as I failed to read what you had written properly...

If you want to surprise the PC's:
Attack with the trolls before the goblins and PCs have noticed each other.
Wait until goblins have been beaten and PC's think combat is over, then attack with the trolls.

Why house rule when you can follow the rules as written without issues with the interpretation of failing to notice all threats.

 

[fjw70]

But in the first example the goblins don't know about the trolls until they jump out. Would you say that the goblins are not surprised because the adventurers gave it away? The trolls in my first example are a third party, why shouldn't they be allowed to surprise the entire group of goblins plus adventurers? By the same token, wouldn't the goblins knowledge of the presence of the trolls in the second example negate the possibility of their being surprised, but not that of the adventurers?

I believe that what many here are proposing is a house rule that states that a noticed threat precludes the possibility of surprise, but for me that places a huge limitation on the conditions under which surprise can happen.

sorry about the edits.

In the gist example the PCs and goblins are surprised since neither side was aware of the trolls. In the second example the goblins give away the trolls by acting in concert with them.

If the PCs and goblins are facing off then when one side decides to start combat initiative is rolled and no one is surprised. The Pcs are not less able to detect the goblins starting combat when they have hidden allies. The goblins need to wait until after the surprise before acting as to not tip their hand.

 

[Hriston]

If the PC's are aware of the other combatants, there is no surprise...

If the characters are confronted with an obviously hostile situation by the guys directly in front of them, then they can't be surprised from a mechanical standpoint by the guys in front of them or in the woods.

I would not grant surprise in this situation, because the PCs know there is a potential fight brewing and are on their guard.

If it's clearly bandits in their path, there is no way that the hidden element will surprise anyone as everyone in the party is expecting combat.

At my table you have to be surprised by all enemies in the fight to be surprised.

...there should be no surprise in this encounter. The PCs know there is a threat, even if they don't know its full extent. They are already braced and ready for trouble. Surprise is when trouble hits somebody who isn't expecting it.

Being aware of one enemy in the fight negates surprise for all.

I just don't see the logic of allowing the PCs to be surprised when they can clearly see the threat of the bandits in the open.

If a group or groups are making a coordinated attack, detection of even a single member of that group(s) spoils the surprise round for everyone.

...if even a single member of the ambushing party tips off their intended victims, then the ambush is spoiled, and there is no Surprise.

You are surprised only if you don't notice any threats. ...If you notice a threat, you are on guard, and you cannot be surprised.

...I interpret the rules as having noticed any part of the opposing side as not being surprised...

...if the goblins attack at the same time as the trolls then that ruins the surprise.

...you can follow the rules as written without issues with the interpretation of failing to notice all threats.

I take back what I said earlier about this being ambiguous and thus up for interpretation. The above stated interpretation of the surprise rules on p. 189 of the PH is actually based on a propositional fallacy, an error in logic that concerns a compound proposition. The proposition in question, if I may paraphrase, is: if (A) a character or monster doesn't notice a threat, then (B) it is surprised. It does not follow that if A is false then B is also false, i.e.: if (not A) a character or monster notices a threat, then (not B) it is not surprised. This is called denying the antecedent, and it happens when the consequent (B) in an indicative conditional, like the statement above, is claimed to be false because the antecedent (A) is false.

 

[Hriston]

...Also, I don't see anything in the rules that gives an immunity from surprise for being on guard, or expecting danger. That's what the Alert feat is there for. I would assume that the PCs are on their guard in most adventuring situations and that the surprise rules are modelling lapses in their level of alertness. If all the players have to do is state that their characters are expecting to encounter a threat to be granted immunity to being surprised, then no one will ever be surprised.

 

[fjw70]

I take back what I said earlier about this being ambiguous and thus up for interpretation. The above stated interpretation of the surprise rules on p. 189 of the PH is actually based on a propositional fallacy, an error in logic that concerns a compound proposition. The proposition in question, if I may paraphrase, is: if (A) a character or monster doesn't notice a threat, then (B) it is surprised. It does not follow that if A is false then B is also false, i.e.: if (not A) a character or monster notices a threat, then (not B) it is not surprised. This is called denying the antecedent, and it happens when the consequent (B) in an indicative conditional, like the statement above, is claimed to be false because the antecedent (A) is false.

I would interpret the statement to say a character is surprised if and only if it doesn't notice a threat. So either both have to be true or both false for the statement to be true.

 

[Azrothan]

It does not follow that if A is false then B is also false

The interpretation/argument is based on the terms used: "a threat", not by claiming that (not A) = (not B).
Any character or monster that doesn't notice [one side] is surprised at the start of the encounter.
Any character or monster that doesn't notice [one individual] is surprised at the start of the encounter.

PHB mentions sides trying to be stealthy and gives the examples [A band of adventurers] and [A gelatinous cube] as one side of the battle gaining surprise over the other.

Now that I've taken time to read up in the book about the potential 3 sides in a combat (or even more, if things get real messy):
Given your example with the trolls above, since no 3-way example is mentioned in the book, I would have to interpret the trolls as being a third side in the conflict, thus surprising both goblins and PCs. (not A = not B obviously not being true)
If the goblins and trolls were allied instead, I find it hard to see that side of the combat trying to be sneaky when one of the parts is in plain sight.

 

[FormerlyHemlock]

But in the first example the goblins don't know about the trolls until they jump out. Would you say that the goblins are not surprised because the adventurers gave it away? The trolls in my first example are a third party, why shouldn't they be allowed to surprise the entire group of goblins plus adventurers?

Because the goblins already see a threat. In psychological terms, they are already in Condition Red: threat identified, entering kill mode.

You can still be surprised when you're in kill mode, but it's not the mechanical D&D version of "surprise" wherein you get no reaction and can't take opportunity attacks. It's just regular old surprise where the tactical situation turns out to be different than you thought: you just used your action to doff your shield, sheathe your sword, and pull our your bow in order to shoot the goblins 100' away from you, but wait! now there's a troll attacking me and I really wish I had known this was about to happen before I doffed my shield.

As for why adventurers don't walk around in Condition Red all the time: I suppose you could, but it would drive you psychotic. The door to the room opens: roll initiative. (Everyone pulls out weapons.) Oh, just kidding it was the chambermaid. Roll initiative. (Everyone readies an action in case she attacks.) She drops the meal platter and bolts. Do you take your opportunity attack? Etc.

TLDR; you can be surprised by a third party in combat, just as you can be surprised by the enemy strategy, but "surprise" from the mechanical perspective only happens to someone who "doesn't notice a threat" and is in Condition White or Yellow. (See http://en.wikipedia.org/wiki/Jeff_Cooper for more on threat conditions.)