The Leapfrog Attack
One-on-One Fleet Tactics
The Convoy Disruption Paradox
The Second-Order Paradox
The Game Designer's Nightmare
The Ken Lowe Judge's Convoy Rules
Pandin's Paradox
The DPjudge Resolution
Ambiguous Convoy Orders
Blockading Gibraltar
Since a convoy isn't disrupted by an attack that fails to dislodge the convoying fleet, the fleet can in essence attack a coastal province while holding a body of water at the same time. Two moves for the price of one!
In Example 3.1, what is the best way for France to attack Piedmont? Any support from the Gulf of Lyon is likely to be cut, so you must support the attack from Marseilles. Attacking with the fleet is sure to succeed, but won't threaten Venice and will probably let Italy occupy the Gulf of Lyon. It is much better to use a "leapfrog" attack, convoying the army from Spain with support from Marseilles.
France: Army Spain -> Gulf of Lyon -> Piedmont.
France: Fleet Gulf of Lyon CONVOY Army Spain -> Piedmont.
France: Army Marseilles SUPPORT Army Spain -> Piedmont.
Italy: Fleet Tyrrhenian Sea -> Gulf of Lyon. (*bounce*)
Italy: Army Tuscany -> Piedmont. (*bounce*)
Italy: Army Rome -> Tuscany. (*bounce*)
Next turn France can either attack Venice or repeat the leapfrog attack against Tuscany!
In both the Black Sea and the Baltic region, you often find yourself with a single fleet opposing a single enemy fleet. In this situation, it is important to recognize that you can never dislodge an enemy fleet at sea with only a single fleet of your own. Therefore, you won't be able to make any headway against the enemy fleet unless it withdraws voluntarily. Your enemy would be wise to consider very carefully before doing this, since it often can't be undone!
The only options, then, for singleton fleets are to attack the other fleet, support into a coastal province or convoy. Attacking the other fleet is usually unsuccessful, but safe. Supporting is likewise usually unsuccessful since the enemy fleet will probably attack you. Convoying, however, is often an excellent option, since there is no risk of the convoy being disrupted. Cutting supports from coastal provinces is also possible, but beware of being helped ashore by your opponent!
In this example, the only sure way to take Prussia requires attacking with the German fleet. Unfortunately, the Russian fleet would almost certainly advance to the Baltic Sea where it would be unassailable. Since attacking this way is too risky and supporting is probably futile, convoying is a good idea. Here is one possibility:
Russia: Army Norway -> Sweden. (*bounce*)
Russia: Fleet Gulf of Bothnia -> Baltic Sea. (*bounce*)
Russia: Army Prussia HOLD.
Russia: Army Warsaw SUPPORT Army Prussia.
Germany: Army Sweden HOLD.
Germany: Army Denmark SUPPORT Army Sweden.
Germany: Fleet Baltic Sea CONVOY Army Kiel -> Livonia.
Germany: Army Kiel -> Baltic Sea -> Livonia.
Germany: Army Silesia -> Prussia.
Germany: Army Berlin SUPPORT Army Silesia -> Prussia.
The German army in Livonia is devastating! Note that this is an example of a no-risk move for Germany. If it works, Russia's fate is sealed. If it doesn't then the status quo will be maintained. Another possibility would be to convoy to Prussia, supported by Berlin and Silesia. This is another instance of the "leapfrog" attack we saw in the previous example.
The basic Diplomacy rules of convoys, supports and cutting of supports can fairly frequently produce paradoxes, such as the one shown in Example 3.3.
France: Army Brest -> English Channel -> London.
France: Fleet English Channel CONVOY Army Brest -> London.
England: Fleet London SUPPORT Fleet Wales -> English Channel.
England: Fleet Wales -> English Channel.
Does the convoyed attack cut the support, thereby protecting the convoy? Or does the supported attack disrupt the convoy, preventing the support from being cut? Both possibilities seem plausible. The original Avalon Hill (1976) rules resolved this particular case by asserting that "a convoyed attack does not protect the convoying fleets." Specifically, the rules state:
If a convoyed army attacks a fleet which is supporting a fleet which is attacking one of the convoy fleets, that support is not cut.
This resolves the issue for simple cases like this one.
Unfortunately, that wasn't the end of it. There are more complicated cases of essentially the same problem, which aren't covered by the 1976 wording. Example 3.4 shows a "second-order" convoy disruption paradox where there are two convoys which are protecting each other's fleets (not their own).
France: Army Brest -> English Channel -> London.
France: Fleet English Channel CONVOY Army Brest -> London.
England: Fleet London SUPPORT Fleet Edinburgh -> North Sea.
England: Fleet Edinburgh -> North Sea.
Russia: Army Norway -> North Sea -> Belgium.
Russia: Fleet North Sea CONVOY Army Norway -> Belgium.
Germany: Fleet Belgium SUPPORT Fleet Picardy -> English Channel.
Germany: Fleet Picardy -> English Channel.
Do both convoys succeed, or are both fleets dislodged? Again, both possibilities seem plausible. By analogy with the first-order case, one would assume that both fleets should be dislodged. However, it is worrisome when we are resorting to analogies instead of rules.
Because of problems like this, Avalon Hill amended the rules in 1982 to specify a more general solution to these problems. The new rules state:
If a convoyed army attacks a fleet which is supporting a an action in a body of water; and that body of water contains a convoying fleet, that support is not cut.
This change handles both the first-order and second-order paradoxes shown above as we would expect.
Unfortunately, some may feel that the cure provided by this rule change may be worse than the disease. Example 3.5 shows a case which was never ambiguous, but has been altered by the new rule.
England: Fleet Irish Sea -> Mid Atlantic Ocean.
England: Fleet English Channel SUPPORT Fleet Irish Sea -> Mid Atlantic Ocean.
France: Fleet Spain (north coast) SUPPORT Fleet Mid Atlantic Ocean.
France: Fleet Mid Atlantic Ocean CONVOY Army Portugal -> Brest.
France: Army Portugal -> Mid Atlantic Ocean -> Brest.
Italy: Fleet Gulf of Lyon CONVOY Army Tuscany -> Spain.
Italy: Army Tuscany -> Gulf of Lyon -> Spain.
What happens in the Mid-Atlantic ocean? Under the original rules, the attack on Spain would cut its support, causing the convoy in the Mid-Atlantic Ocean to be disrupted. The fact that the attack on Spain is by a convoyed army was irrelevant.
Under the new rules, however, the support (of an action in a body of water containing a convoying fleet) would not be cut, and the Mid-Atlantic convoy would succeed. This remains true even if the army in Marseilles supports the attack on Spain, thereby dislodging it.
Some maintain that this result is illogical, and that the original rules were better in this case. What's really unfortunate is that the cases the new rules mess up are probably more common than the pathological cases they were meant to fix.
Note that The Pouch's e-mail and Web-based adjudicator, The DPjudge, uses this rule (see below for more details), but is also able (by use of a specific game flag) to resolve convoy paradoxes using a different rule as well.
The Ken Lowe PBEM judge tries to get the best of both worlds, but it does
so at the expense of simplicity.
For all you computer programmers out there, this should be clear as crystal! The rest of you will probably need to work through a few examples to get it straight. You'll find that the judge rules get both the first- and second-order cases right without the unpleasant side-effects of the 1982 rules.
So is this the final word on this topic? I doubt it. There are probably even more obscure cases where the judge rules don't produce the "correct" result (assuming everyone even agrees what the most reasonable result is). But they do seem to be a workable solution for at least the medium-term.
Just when you thought all of these convoy paradoxes were behind us, up pops Pandin's Paradox. This one is even more unsettling than the previous ones.
France: Army Brest -> English Channel -> London.
France: Fleet English Channel CONVOY Army Brest -> London.
England: Fleet London SUPPORT Fleet Wales -> English Channel.
England: Fleet Wales -> English Channel.
Germany: Fleet North Sea SUPPORT Fleet Belgium -> English Channel.
Germany: Fleet Belgium -> English Channel
Like the original example (3.3), the convoyed army is trying to cut a support directed against the convoying fleet. But this time, that attack is actually defending the convoying fleet by standing-off an equally well supported attack. If the convoy is assumed to succeed, then the convoy ends up being disrupted. Conversely, if the convoy is assumed to fail, then the convoy isn't disrupted!
In the ordinary convoy disruption paradox there are two possible resolutions, each of which is self-consistent -- the difficulty is choosing between them. In Pandin's paradox there are two possible resolutions, neither of which is self-consistent!
Both the original and revised Avalon Hill rules result in the support not being cut by the convoyed attack, even though this results in the convoy not being disrupted. The judge rules, on the other hand, result in both the support being cut and the convoy being disrupted. The judge rules could be brought into line with the Avalon Hill rules in this case by changing step 2 of the process slightly to read:
2) Any armies being convoyed by fleets that would be dislodged depending on whether further supports are cut are flagged "maybe no convoy".
This makes this step blind as to whether the convoyed attack is cutting a support which is attacking or defending the convoying fleet.
The Pouch's DPjudge resolves the paradoxes by implementing the 1982 rule. That is, a convoyed army cannot cut a support that is offered in defense of or for an attack on the position of any convoying fleet -- not even if the army dislodges such a supporting fleet. (All other supports are cuttable as normal, but supports directed against a convoying fleet cannot ever be rendered cut by a convoying army.)
This rule nicely resolves the paradoxes, leaving the only possible (though rare) inconsistency described in Example 3.5 that a valid support which establishes a convoying fleet as a beleaguered garrison could be offered by a dislodged fleet. More information can be found in the DPjudge Common Questions list.
The 1976 Edition of Diplomacy states that ambiguous convoy routes are allowed, but if any of the possible routes is disrupted, then the army is not convoyed. Apparently the motivation was to make players choose a specific convoy route, but without penalizing players who write confused, but nonetheless intelligible orders.
The 1982 Edition modified this rule so that the convoy succeeds unless all routes are disrupted.. This change adds a new tactical element to the game by permitting backup convoy routes.
The current judge rules essentially correspond to the 1976 rules by forcing players to specify the convoy route in their orders. Thus there can be no ambiguity. However, I suspect this choice was made to avoid complexity in the judge programming, and not because of a strong preference for the 1976 rules. It would certainly be possible to implement the revised rules instead (although there are probably better things to work on). Would this be better? Does anyone care? Has anyone ever seen a situation where a backup convoy could have made a difference?
Italy: Army Tunis -> Naples.
Italy: Fleet Tyrrhenian Sea CONVOY Army Tunis -> Naples.
Italy: Fleet Ionian Sea CONVOY Army Tunis -> Naples.
In this contrived example, Italy increases the likelihood of a successful convoy in face of uncertainty about his neighbors' intentions. Realistically, though, supporting one fleet with the other would usually be a better choice.
Italy: Army Tunis -> Naples.
Italy: Fleet Tyrrhenian Sea CONVOY Army Tunis -> Naples.
Italy: Fleet Ionian Sea SUPPORT Fleet Tyrrhenian Sea.
The only cases where this strategy fails and the other succeeds is if France attacks with support and Turkey cuts the support from the Ionian Sea without dislodging it.
Here's a simple position that everyone should know. England (or any Northern naval power) can permanently blockade Gibraltar using only three fleets. No conceivable attack from the Mediterranean can ever break through. The only possible way to get though is to build a fleet in a Northern port to assist in the attack.
England: Fleet Mid-Atlantic Ocean HOLD.
England: Fleet Portugal SUPPORT Fleet Mid-Atlantic Ocean.
England: Fleet Irish Sea SUPPORT Fleet Mid-Atlantic Ocean.
The fleet in the Irish Sea could also be in the North Atlantic Ocean or the English Channel instead. Even if the enemy has fleets in Spain (South Coast), the Western Mediterranean and North Africa, they cannot break through.
This position is one of the simplest examples of a stalemate line -- a position which can never be broken through. They are particularly useful for countries that cannot win, but that want to assure themselves of a place in any draw. Over 50 different stalemate positions have been catalogued in Stalemates A to Y, which has now been republished in The Diplomatic Pouch. See Robert Bryan Lipton's "A Series of Progressive Northern Stalemate Positions" for a detailed discussion of this particular position.
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