move resolution bug

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dank57
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move resolution bug

#1 Post by dank57 » Sun Sep 12, 2021 1:15 am

Apologies if this has been reported before, or if the move resolution rules have changed since I was last playing.

In Spring '02 in game 374776 (https://webdiplomacy.net/board.php?gameID=374776), France order Pic S Par -> Bre, and England ordered Eng C Bre -> Pic. Support should have been cut (since the attack in this convoy is considered to come from Eng); it wasn't.

Dan

dank57
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Re: move resolution bug

#2 Post by dank57 » Sun Sep 12, 2021 2:48 am

Well ... weird. Backstabbr doesn't even allow the option of moving by convoy, and PlayDiplomacy's move resolution page seems to show that support isn't cut. My guess is it was just easier to code this way, but it doesn't follow the resolution rules that were used for many years.

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Re: move resolution bug

#3 Post by A_Tin_Can » Sun Sep 12, 2021 3:01 am

the attack in this convoy is considered to come from Eng
I don't believe this is in the rulebook. I think that's a convenient restatement of this rule (which *is* in the rulebook):
A Convoyed Attack Doesn’t Cut Certain Supports
A convoyed Army doesn’t cut the support of a unit supporting
an attack against one of the Fleets necessary for the Army to
convoy
The restatement is convenient, because it's easier to follow. However, it doesn't produce the right answer in the case that you've linked.

I think a better way to restate it is "for the purposes of cutting support, convoyed attacks are considered to come from the source province and all fleets in the convoy". (But even that isn't right, because you *can* cut support with a convoy if you still have another valid convoy route)

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Re: move resolution bug

#4 Post by RoganJosh » Sun Sep 12, 2021 3:09 am

Yeah, I don't think this scenario is in the rulebook either.

It's one of the scenarios I checked before, and if I remember correctly all websites/apps has the same outcome as webDip: Bre will not be allowed to cut the support of Pic, even though it's moving via convoy.

I'm not sure where dank used to play.
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Re: move resolution bug

#5 Post by A_Tin_Can » Sun Sep 12, 2021 3:10 am

Backstabbr doesn't even allow the option of moving by convoy,
See here:

https://www.backstabbr.com/sandbox/5642260222574592

Backstabbr resolves this the same way that webdip does.

Note that "via convoy" is only necessary if the convoying fleet doesn't belong to the player who owns the army - see the bottom right of page 16 in the rulebook: https://media.wizards.com/2015/download ... _rules.pdf

(it's a quirk of webdip that have to say via convoy even if you own the army)
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Re: move resolution bug

#6 Post by RoganJosh » Sun Sep 12, 2021 3:13 am

A_Tin_Can wrote:
Sun Sep 12, 2021 3:01 am
I think a better way to restate it is "for the purposes of cutting support, convoyed attacks are considered to come from the source province and all fleets in the convoy". (But even that isn't right, because you *can* cut support with a convoy if you still have another valid convoy route)
I'm not sure what you are actually saying here. The convoy route was valid. Why would having two valid convoy routes make a difference?
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Re: move resolution bug

#7 Post by RoganJosh » Sun Sep 12, 2021 3:19 am

Oh, I just realized you were talking on cutting support for an attack on the sea province containing the fleet. Yes, then having two routes makes a difference.

Cutting support for an attack on the original province of the army, as in this case, it doesn't matter how many convoy routes you have. That support won't be cut.
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dank57
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Re: move resolution bug

#8 Post by dank57 » Sun Sep 12, 2021 3:45 am

This may help (long story short: you're all right!). The best I can tell, Webdip's adjudicator test cases come from http://web.inter.nl.net/users/L.B.Kruijswijk. The test case we're talking about is http://web.inter.nl.net/users/L.B.Kruijswijk/#4.A.4. This shows that, a couple decades ago (okay, I'm dating myself), there were arguments both ways (including from Calhamer!), but the issue seems to be settled now.

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Re: move resolution bug

#9 Post by dank57 » Sun Sep 12, 2021 4:39 am


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Re: move resolution bug

#10 Post by RoganJosh » Sun Sep 12, 2021 1:32 pm

I would have preferred it if the rule was different. Would have been more consistent across rules if the attack counted as coming from the see only. As it is now, in terms of cutting support the attack comes from the sea and from the land. But for all other issues (head-to-head movement, possible retreats, etc..) it counts as if the army is coming form the sea only.

But consistency across platforms also has value. So since all adjudicators agree, it is what it is.
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Re: move resolution bug

#11 Post by dank57 » Sun Sep 12, 2021 3:31 pm

Agreed. It was kind of fun to research an old adjudication issue. Sorry for my ignorance above, I thought this was a settled issue back in the day ... apparently not.

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Ienpw_III
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Re: move resolution bug

#12 Post by Ienpw_III » Mon Sep 13, 2021 4:15 am

This is an interesting issue, thanks for sharing. For my part it makes sense that the principle of not being able to cut support with the very unit being attacked takes precedence.

Per the current Avalon Hill rulebook's resolution rules, "13. Support is cut if the unit giving support is attacked from any province except the one where support is being given." This implies that convoying the unit has no effect, and there's no other indication that this rule is to be superseded in this case.

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Re: move resolution bug

#13 Post by RoganJosh » Mon Sep 13, 2021 5:16 am

Ienpw_III wrote:
Mon Sep 13, 2021 4:15 am
13. Support is cut if the unit giving support is attacked from any province except the one where support is being given.
The issue lies in the phrase "attacked from." Does the attack come from the land or does the attack come from the sea? That's the ambiguity.

Reading this again, the situation is actually more inconsistent than what I remembered.

Right, if the attack would count as coming both from the sea and form land, then the supporting unit would be attacked both from the sea and from the land. So its support would be cut, according to Cutting Support rule.

So what's really going on is that, if a convoyed army is attacking a fleet supporting an attack on one of the convoying fleets, then it is counted as if the army is coming only from the sea. But if a convoyed army is attacking a unit supporting an attack on its original province, then it is counted as if the army is coming only from its original province.
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Re: move resolution bug

#14 Post by bozotheclown » Mon Sep 13, 2021 6:32 am

RoganJosh wrote:
Mon Sep 13, 2021 5:16 am
Ienpw_III wrote:
Mon Sep 13, 2021 4:15 am
13. Support is cut if the unit giving support is attacked from any province except the one where support is being given.
The issue lies in the phrase "attacked from." Does the attack come from the land or does the attack come from the sea? That's the ambiguity.

Reading this again, the situation is actually more inconsistent than what I remembered.

Right, if the attack would count as coming both from the sea and form land, then the supporting unit would be attacked both from the sea and from the land. So its support would be cut, according to Cutting Support rule.

So what's really going on is that, if a convoyed army is attacking a fleet supporting an attack on one of the convoying fleets, then it is counted as if the army is coming only from the sea. But if a convoyed army is attacking a unit supporting an attack on its original province, then it is counted as if the army is coming only from its original province.
I have seen this discrepancy explained in terms of "real word" implications, which I think makes sense. In the case being discussed, if the army in Bre. is busy trying to convoy to Pic., it is not available to defend against an attack from Pic. In the other case, a convoyed army can't help defend against an attack on a fleet convoying it, because the fleet can't simultaneously defend against an attack and convoy an army.

In other words, I think the adjudications are meant to not allow any unit to perform 2 tasks simultaneously, which is the idea behind units not being able to cut support on attacks against them.
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Claesar
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Re: move resolution bug

#15 Post by Claesar » Tue Sep 21, 2021 6:28 am

bozotheclown wrote:
Mon Sep 13, 2021 6:32 am
I have seen this discrepancy explained in terms of "real word" implications, which I think makes sense. In the case being discussed, if the army in Bre. is busy trying to convoy to Pic., it is not available to defend against an attack from Pic. In the other case, a convoyed army can't help defend against an attack on a fleet convoying it, because the fleet can't simultaneously defend against an attack and convoy an army.

In other words, I think the adjudications are meant to not allow any unit to perform 2 tasks simultaneously, which is the idea behind units not being able to cut support on attacks against them.
I'm not sure that's it..

F A Bre-Gas
G A Pic-Bre
G A Bur-Gas

The French army defends both Gas and Bre against the German invaders. It performs 2 tasks simuktaneously.

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