Stay back! The joy of OAs.

[Valdier]

No, because polearm gamble doesn't say anything about "when an enemy takes a move action," it says "when an enemy enters a square adjacent to you."

Ahh, I see

 

[Plane Sailing]

That's a reasonable conclusion, but it's incorrect.

Opportunity Attacks are immediate actions. There are two types of immediate actions: interrupt, and reaction.

What you describe above is a reaction. Reactions take place after the triggering action is completed.

With respect, I think that MrMyth has the more compelling case at the moment. I think his conclusion is both reasonable and correct.

Your statements are correct in the general case, but Polearm Gamble introduces a new special case.

 

[MeMeMeMe]

That's a reasonable conclusion, but it's incorrect.

Opportunity Attacks are immediate actions. There are two types of immediate actions: interrupt, and reaction.

Actually, opportunity attacks are Opportunity Actions, not Immediate actions. Check out PHB p268. Opportunity Actions do not have the same effect as an interrupt.

So, the attacker marches up to the polearm wielder who gets his free attack, and then the attacker keeps moving.

 

[Zaruthustran]

Actually, opportunity attacks are Opportunity Actions, not Immediate actions. Check out PHB p268. Opportunity Actions do not have the same effect as an interrupt.

So, the attacker marches up to the polearm wielder who gets his free attack, and then the attacker keeps moving.

Hmm, I'm away from my books, but I recall that Opportunity Actions are immediate actions. I'll look that page up when I get home.

In any case, though, if that OA hits then the target can't keep moving. He has to stop. That's just a class feature of the fighter.

Plane Sailing, I'll have to take another look but based on those rules I quoted, I'm pretty sure the OA stops the incoming move cold--the move adjacent is interrupted and doesn't finish resolving. The example in the quote is very clear: the example character's shift is triggered by an attack, but the shift takes place *before the attack resolves*.

In the same way, the OA from Polearm Gamble is triggered by a move adjacent, but takes place before the move adjacent resolves.
In a way, it takes place when the enemy declares that he's moving adjacent but before he actually moves (not that "declare" is a mechanic in 4e; just saying that by way of explanation).

That seems pretty clear to me, but I've had these rules for less than a week--I'm definitely not an expert. I'm curious, though: what is the basis for your alternative conclusion?

 

[MeMeMeMe]

In any case, though, if that OA hits then the target can't keep moving. He has to stop. That's just a class feature of the fighter.

Let's say that's true (but see next paragraph): the character moves into the square and triggers the opportunity attack. He gets hit, and stops. At this point he has moved into the square - so isn't held back the way this build is dependent on.

But he isn't actually stopped. The fighters class feature Combat Challenge is triggered "when a marked enemy that is adjacent to you shifts or makes an attack that does not include you, you can make a melee basic attack against that enemy as an immediate interrupt."

This is an immediate interrupt, and it's this which is being relied upon to stop the movement. But this ability isn't being used: the polearm glaive (a) isn't an immediate interrupt, and (B) isn't triggered by a shift or an attack against someone else.
So, the movement isn't stopped.

A more general point about the immediate interrupt gained from combat challenge. This says, "If an interrupt invalidates a triggering action, that action is lost." So, you have to stop the person from being able to move, to cause him to stop moving. If the attack you made knocked him prone, that would work. But otherwise, the fighter makes his immediate interrupt attack, and then the target moves on. But note again that the fighter's combat challenge ability does not apply against move actions. It does work against shifts, but it doesn't stop the shift occurring.
The marked target knows that if he does shift away, he will get attacked - but he can shift away anyway, if he chooses to. It's a deterrent, not a block.

<snip>

In the same way, the OA from Polearm Gamble is triggered by a move adjacent, but takes place before the move adjacent resolves.
In a way, it takes place when the enemy declares that he's moving adjacent but before he actually moves (not that "declare" is a mechanic in 4e; just saying that by way of explanation).

As noted above, this isn't right. There are several reasons above why this tactic doesn't work, but the most important one is the first one: polearm gambit is an opportunity action, and not an immediate action.
There are two types of actions you can take after a trigger: Opportunity Actions, and Immediate Actions.
There are also two types of Immediate Actions - Reactions and Interrupts. But an Opportunity Attack is neither, it is an opportunity action.

 

[bjorn2bwild]

Dig this build, although, I agree that it wouldn't stop movement to adjacent. That's also ok, or at least isn't terrible, considering once they're next to you, you get OA's if they move in any way.

I've put together most of a character using almost this exact same build, but using Iron Vanguard for the paragon path. It has some awesome synergies for polearm users and the wide variety of pushing powers they have.

 

[Kordeth]

But he isn't actually stopped. The fighters class feature Combat Challenge is triggered "when a marked enemy that is adjacent to you shifts or makes an attack that does not include you, you can make a melee basic attack against that enemy as an immediate interrupt."

No, you're confusing two different fighter abilities. Combat Challenge works as you describe. Combat Superiority says a target hit by the fighter's OA stops moving if movement was what provoked the OA.

As noted above, this isn't right. There are several reasons above why this tactic doesn't work, but the most important one is the first one: polearm gambit is an opportunity action, and not an immediate action.
There are two types of actions you can take after a trigger: Opportunity Actions, and Immediate Actions.
There are also two types of Immediate Actions - Reactions and Interrupts. But an Opportunity Attack is neither, it is an opportunity action.

The attack granted by Polearm Gamble is plainly stated to be an Opportunity Attack, and it's provoked by a target entering an adjacent square. Opportunity Attacks interrupt the action that trigger them. In other words, this tactic works just fine, once per opponent's turn.

 

[MeMeMeMe]

No, you're confusing two different fighter abilities. Combat Challenge works as you describe. Combat Superiority says a target hit by the fighter's OA stops moving if movement was what provoked the OA.

Ah yes, you're quote correct. Oops.
That doesn't change one thing though.

The attack granted by Polearm Gamble is plainly stated to be an Opportunity Attack, and it's provoked by a target entering an adjacent square. Opportunity Attacks interrupt the action that trigger them. In other words, this tactic works just fine, once per opponent's turn.

Opportunity Attacks do not interrupt the action that triggered them, by the specific definition the game uses for the term "interrupt".
An immediate interrupt does interrupt an action. An opportunity attack is not an immediate interrupt action.
An opportunity action, like an opportunity attack, is triggered, but does not interrupt. Have a look at page 268, and note that the Opportunity Actions and Immediate actions are different types of actions. Only the imemdiate interrupt, a subtype of immediate actions, has the quality of rolling back a triggering action to stop it occurring.

So, with my embarrassing little overlooking of combat superiority aside , we are left with:

The attacker moves towards the polearm user, steps into the space that triggers the opportunity attack, and stops moving at that point: he does not move back to the previous square.

MyMyth's interpretation is, I'm sure, the correct one:

Well, that's the difference between normal Opportunity Attacks, and those granted by Polearm Gamble.

A normal Opportunity Attack triggers when the target attempts to leave the square - and thus, if the fighter hits him, he doesn't succeed in moving away.

Polearm Gamble grants an OA in response to the enemy having entered the square next to you - thus, by the time you swing, he's already in place and his movement can't be stopped.

At least, that is how I'm reading it thus far.

With the caveat being that since the fighter has Combat Superiority, the attacker can't move beyond that point.

 

[Kordeth]

An opportunity action, like an opportunity attack, is triggered, but does not interrupt. Have a look at page 268, and note that the Opportunity Actions and Immediate actions are different types of actions. Only the imemdiate interrupt, a subtype of immediate actions, has the quality of rolling back a triggering action to stop it occurring.

Did you happen to note the last bullet point under the definition of "Opportunity Action?" The one that says "An opportunity action interrupts the action that triggered it?"

 

[MeMeMeMe]

Hmm. Yes. Yes, I did. <hangs head in shame>

One thing is puzzling though. Why there is different text under the two sections.
In Opportunity Actions, it has the text you list, and that is the full entry.

In Immediate Actions, which are a different type of action, it lists Immediate Interrupt - and has a long section describing how interrupts actually work. But it's not clear to me whether it is describing how immediate interrupts work, or how all interrupts work.

You'd think each of those two sections (Opportunity Actions and Immediate Interrupt Actions) there'd be text like "this Interrupts an action," with a second seperate definition "interrupts undo the action which triggers them."
It seems to me that leaves open the interpretation that Immediate Interruptions work like that, but Opportunity Actions might not. Then again, why mention that opportunity actions interrupt actions, if they don't work like that? <confused>