# Does moving around an opponent trigger an Opportunity Attack?

I'll try to be as specific as possible.

In the first diagram, creature A wants to attack creature B.
In the second diagram, it moves 5 squares to the back of creature B and attacks.

· · · A · · ·  |  · · · A · · ·
· · · · · · ·  |  · · · 1 2 · ·
· · · B · · ·  |  · · · B 3 · ·
· · · · · · ·  |  · · · 5 4 · ·
fig. 1            fig. 2


Does this move action provoke an OA from creature B?
If yes, then at which square?

P.S. I 'm aware that this move can be completed in 3 squares, but for the sake of simplicity let's stay at 5.

• This seems to be a straightforward "I didn't read the right part of the book" question. That makes me wonder if the problem is something else, and this is just the puzzle piece you're hoping will solve the larger problem? – SevenSidedDie Sep 15 '14 at 23:39
• @SevenSidedDie the illustration looks like an edge case for an interpretation of "leaves a square adjacent to you" where the after-movement square isn't adjacent, i.e., in this picture a player could claim that they never "leave" B. – Peteris Sep 16 '14 at 14:37
• @Peteris Only if the person making that claim is illiterate in English. The book says nothing of "leaving the set of those squares which are adjacent", it says "leaving an adjacent square", which cares nothing for whether the square you go to is also adjacent or not. The square marked 1 in the diagram is a square, and it's adjacent, thus it is an "adjacent square", and leaving it provokes. – Matthew Najmon Sep 17 '14 at 1:29

The rules for provoking opportunity actions (from PHB page 290) is:

If an enemy leaves a square adjacent to you, you can make an opportunity attack against that enemy.

Thus every square of movement apart from the first would be considered as provoking movement since each other square creature A is leaving is adjacent to creature B.

Just remember though that creature B may only take one opportunity action during creature A's turn, but it could hold off taking the opportunity action on earlier squares to instead take the opportunity action on say square 4 or 5 if it chose.

• Of course, B wouldn't necessarily know that A was going to provoke three more AoOs after the first, but you never know. – GMJoe Sep 16 '14 at 2:35
• @GMJoe No B doesn't know in advance how many opportunities will be provoked, but it does know for each square of movement where A is going, and thus can hold its opportunity action until it wants to take it eg. A moving to a square from which it wouldn't provoke. – Ken Herbert Sep 16 '14 at 3:38
• Oh, I thought that movement was taken one square at a time, with the option of changing course during any square of that movement if new information arose as a result of the new positioning. Thanks for clearing that up. – GMJoe Sep 16 '14 at 4:24
• @GMJoe By "for each square of movement" I meant that movement is taken one square at a time, sorry if that was unclear. Basically for each square moved: A indicates which space it is moving into, B reacts if it wishes, A moves into that square. After the first square A is now adjacent to B, so B can effectively choose to hold its opportunity action until A moves to a space that is no longer adjacent (knowing that further movement from A probably won't provoke from that square). Of course if A stops moving, B's opportunity action is wasted. – Ken Herbert Sep 16 '14 at 4:55
• @winterblood I was always of the impression that in RAW (have to look it up though) you have to declare the whole move action at once; Maybe B doesn't know the remainder of the movement after that single square and has to decide with the limited information, but A can't change course depending on, say, if AOO's hit (except when taking a second move action). – Peteris Sep 16 '14 at 14:30

The move provokes a potential OA as an interrupt to every movement after 1.

According to PHB 290, "if an enemy leaves a square adjacent to you," you can make an OA. This first happens when A moves from 1 to 2. B can choose to make that OA or to wait. Each additional movement provokes a chance for an OA, and B may choose to take their OA at any time.

Normally you can make a single opportunity action per turn, but there could be a rule that allows you to make more than one. If B was somehow allowed to take as many OAs as they wanted, they could make an OA four times during the movement in question.

The OA is an interrupt, although it does not stop A from continuing their movement unless some rule says it does: for instance, Minotaurs can knock people prone via an OA, which would stop A in their tracks. As a result, the exact moment when the first OA can occur is "just before A leaves square 1."

• Most of this is right. However, even with Combat Reflexes or other means of raising the per-round AoO cap, you can still only make one AoO per provoking action, so while you could take any one of those four provocations, and still make more AoOs later, you could not take all of those four provocations, as they all originate from the same action, a move by character A. – Matthew Najmon Sep 17 '14 at 1:31
• @MatthewNajmon Correct, as long as you don't have access to a rule that says you can make more than one OA. On glancing through the compendium I don't see one, but it's possible. – Gregory Avery-Weir Sep 17 '14 at 11:17