The Stirring Case of the Double French

[woelpad]

I challenge you to solve the latest Sherlock Holmes puzzle (riddle, brain teaser, ...) in the Pouch Zine, called "The Stirring Case of the Double French".

http://www.diplomatic-pouch.org/Zine/S2018M/Holmes/stirring.html

Synopsis: You're given a map where all units have been removed and only ownership of supply centers is shown. Your task is to find out where the first army from Paris and the army from London are on this map. No information on the current year or season are given, nor should you assume anything about the starting position. The real question you should ask yourself is: "How was this map constructed?" The only other hint is in the title.

Feel free to expose your answer and discuss how you derived it. The correct solution will be published sometimes later this month in the upcoming F2018M Zine.

Code: Select all

AUSTRIA (0/8)  BER BUD BUL GRE LVP NWY SPA VIE                                   
ENGLAND (0/4)  DEN LON NAP SER                                                   
FRANCE  (0/3)  BRE MAR PAR                                                       
GERMANY (0/2)  MUN VEN                                                           
TURKEY  (0/17) ANK BEL CON EDI HOL KIE MOS POR ROM RUM SEV SMY STP SWE TRI TUN WAR

[Jack007]

Just one question: Is this a map from a real game, or is it constructed?

[woelpad]

Just one question: Is this a map from a real game, or is it constructed?

It's constructed.

[woelpad]

No takers? As it's almost Christmas, let me put you on the right track.

On this map France is trying to conquer the whole map in the shortest amount of time, by conquering centers and building new units at such a high rate that it nearly doubles in size every year. Hence "Double French". Which centers it captures every year is indicated by the colors of the supply centers, with centers of the same color captured in the same year.

Well then, where did the two armies (Paris and London) end up?

[GhostEcho]

Frankly I didn't even begin to try to guess before because the puzzle as written made no particular sense. The map (in the ordinary run of things) looks like a Turkish solo attempt (albeit on a messy board), and talking about where the "army Paris had already arrived" threw me a bit.

With this latest hint, I think we have to assume the entire board, however it got here, is cooperating to help French expansion: "Which centers it captures every year is indicated by the colors of the supply centers, with centers of the same color captured in the same year." I don't see how you can possibly figure that out from the initial text of the puzzle, but whatever.

So. France presumably starts with 3 units, whether or not they're in their home centers. But since the "army from Paris" is mentioned, I'm going to assume they do. France has to take the "German" centers first, because three units can't take four (or more!) centers. It's unclear from the puzzle whether the board should be assumed to have more than the French units and an English army from London, or whether the A (from) Lon is still in London at the start of the puzzle - or if the dots are just there as targets.

At any rate army Paris, based on these assumptions, has to have gone to Munich first.

"England" has to be the next target, because you can't jump from 5 to take 8. So A Par has to go next to Den.

France now has 9 centers (but only 8 units at most), enough to tackle the "Austrian", but not the "Turk". Denmark could move to Norway or Berlin. London can also get to Norway, but no other French unit can reach Liverpool, so Lon must go to Liverpool, and Denmark to Norway.

France now has 17 centers (but only 11 units), and my assumptions about the puzzle collapse, because there's no way 11 units can take the 17 "Turkish" centers. But if the goal is to take as many of them as possible, then Norway (from Paris originally) probably ends up in Moscow, because no other French unit can get there.

London is ?????

And that's all I got.

[woelpad]

The text was deliberately vague to allow all kinds of interpretations. It's a question of imagination, I guess. On another forum there were people throwing out various ideas and I simply had to steer them towards the right one.

Let's try and see if we can still get some collective effort going here. You're facing two problems: army London's genesis and the French build cap. There's one trick that resolves both. Which?

[woelpad]

Not really a trick. A rule variant...

[GhostEcho]

Not really a trick. A rule variant...

Are there are set of rules you set up for the Sherlock Holmes puzzles? I've glanced at them before but promptly moved on, because they all look opaque. If this one is a representative sample of the rest, that seems like a solid move on my part, though now I've started on it I want to work it out.

Also, your initial synopsis said "find out where the first army from Paris and the army from London are on this map", when the task is evidently to figure out where they will be after several years of handing France the board.

So, some thoughts for future puzzles, not that everybody necessarily shares my tastes:

1) I don't personally care for puzzles where figuring out the rules for the puzzle is part of the puzzle.
2) If figuring out the rules for the puzzle is part of the puzzle, then the hints should be much more, uh, hint-y and less "here's part of the answer".
3) Information provided in the puzzle should be accurate unless the solvers are specifically warned otherwise.

Anyway.

I think we must have to assume build-anywhere rules, but now there's another ambiguity.

Option 1) England is eliminated, and that's a downer.
Option 2) England survives: for this to occur, England must be in one of the Turkish centers after the third year of movement (because France needs 17 to take 17, so England can't be limiting France to 16), and able to move back to a French-owned center to survive, but of course then France doesn't actually take the whole board.

The problem with Option 2 is that A Lon could be just about anywhere, assuming cooperation. If France convoyed it to the continent, it could sit in Bel and slip back to Paris, for example. It could even be back in London - move up to Edi, camp out, move back in the final year, French unit takes Edi from Lvp. And I don't see enough information given to figure out what kind of "non-cooperation" we might be able to assume. So my thought is there has to be a verbal hint in the text of the puzzle, but I'm not sure where to start following that line.

On the French side of things I'm now leaning towards A Paris ending up in St. Petersburg rather than Moscow, because it looks harder to get a new-build unit there in time given the order of conquest specified. But it might be Den -> Ber -> War, too, because build-anywhere gives more flexibility. Would actually have to count things out to be sure.

[woelpad]

I agree that further hints might have been more enjoyable. I hurried it a bit, wishing it to be solved before the solution article was published. Once the riddle is deciphered, the problem becomes one of reconstructing the complete game, not just the two units that appear in the riddle. Still not a trivial task, still fun, but a different kind of challenge.

You still have a few misconceptions though. In this game France is the only power playing. None of the other powers put any units on the board, ever. The London army is the one that France builds after it captures London. As London gets captured in the second year, along with the other blue centers, the first time that France can build there is a year later, in Winter 1903. This is also the last time for a build in London, as the whole board gets conquered the next year. That means you know exactly where this army starts the year and only need to find out which center it conquers. You might make a fair guess, but to be absolutely certain you'll need to trace the paths of every other unit on the board.

Anyway, you can read how Holmes & co. solved the riddle by following the link below. Note the break after they decipher the riddle, giving the reader a chance to tackle the second part by themself, just as I attempted to do here. This approach is pretty common in these puzzles, accommodating to different kinds of people.

http://www.diplomatic-pouch.org/Zine/F2 ... irred.html