The Seven Empires - Solution

The maps and tables depict positions and moves in games of Diplomacy. Diplomacy has 7 players, each playing a Great Power from just before WWI. The 7 countries are Austria-Hungary (red), England, France (blue), Germany (gray), Italy (green), Russia (white), and Turkey (yellow). The tables show the orders for all the countries except for England, and the maps show the starting positions of their Armies and Fleets.

The first step is to identify the images for each board. It turns out that each image clues a battle:

Each of these historical battles involves a Diplomacy country on each side, and each one corresponds to a battle on the board between those two countries. These battles on the board all involve the attacking country moving into a province and the defending country holding in that province. Both the attacker and the defender are potentially supported by other units. The attacker wins if they have a strictly greater number of units supporting them than the defender, while the defender wins if they have an equal or greater number of supports.

However, with just the given orders, the battles on the board don’t result in the historical victors winning. The only way to have the correct historical winners is to involve the missing English units, all of which are Fleets (since no Armies are missing). One English Fleet is involved in each battle, and the positions of all the English Fleets can be completely determined.

For each battle involving England, the English Fleet needs to be present to take part in the battle, either to hold against an unsupported attack (if England is supposed to win), or to be dislodged by a supported attack (if England is supposed to lose). In either case, the Fleet must be in the province being attacked by the opposing country.

For the battles involving two other countries, there are a number of different ways the English Fleet can affect the battle:

1. By supporting the country that is supposed to win the battle. The Fleet can support the attack on the defender’s province, or it can support the defender holding in that province. For an English Fleet to be able to support in either case, it must be located in an adjacent province, and it must be able to itself move into the province where the battle is taking place. This means that each of the two provinces must be either a sea province or a coastal land province. Furthermore, if these are two adjacent coastal provinces, their border must be along the coast: for example, an English Fleet in Smyrna can’t move into or support into Ankara, since the border between these provinces is entirely inland.
2. By cutting one of the supports on the side that is supposed to lose the battle. This simply involves the English fleet moving from its current province to the province of the unit giving support. The same restrictions on the two provinces as explained in the previous case still apply to the English Fleet.
3. By convoying an attacking army to the province it’s attacking. This requires the English Fleet to be specifically in a sea province (not a coastal province). It could either convoy the army by itself, between two coastal provinces that both border the same sea zone, or it can be part of a connected chain of convoys that connect the army’s origin and destination provinces via multiple connecting sea provinces.

Here are the details of the battles, as well as maps showing all countries’ orders. A circle means a hold, solid arrows are moves, dotted arrows are supports, and light blue arrows are convoys. English fleets are purple.

Board 1 Battle	Historical Winner/Loser	Battle Location on Board	English Fleet Location	English Fleet Order	Type of Action
Borodino	France/Russia	Naples	Ionian Sea	Fleet ION C Army ALB-NAP	Convoying the attacking army
Champagne (2nd)	Germany/France	Serbia	Aegean Sea	Fleet AEG-GRE	Cutting the defender’s support
Chesme	Russia/Turkey	Tuscany	Rome	Fleet ROM S Fleet GOL-TUS	Supporting the attacking unit
Jerusalem	England/Turkey	Venice	Venice	Fleet VEN H	Participating in the battle
Kilimanjaro	Germany/England	Irish Sea	Irish Sea	Fleet IRI H	Participating in the battle
Polar Star	Germany/Russia	Ankara	Constantinople	Fleet CON S Fleet BLA-ANK	Supporting the attacking unit
Thousand Islands	England/France	Tunis	Tunis	Fleet TUN H	Participating in the battle
Board 2 Battle	Historical Winner/Loser	Battle Location on Board	English Fleet Location	English Fleet Order	Type of Action
Bagration	Russia/Germany	London	Yorkshire	Fleet YOR S Army WAL-LON	Supporting the attacking unit
Compass	England/Italy	North Africa	North Africa	Fleet NAF H	Participating in the battle
Galicia	Russia/Austria	Portugal	Spain (either coast)*	Fleet SPA (sc/nc) S MAO-POR	Supporting the attacking unit
Isonzo (1st)	Italy/Austria	Belgium	North Sea	Fleet NTH S Army BEL H	Supporting the defending unit
Magenta	France/Austria	Syria	Eastern Mediterannean Sea	Fleet EAS S Army AMY-SYR	Supporting the attacking unit
Scimitar Hill	Turkey/England	Clyde	Clyde	Fleet CLY H	Participating in the battle
Trafalgar	England/France	Trieste	Trieste	Fleet TRI H	Participating in the battle
Board 3 Battle	Historical Winner/Loser	Battle Location on Board	English Fleet Location	English Fleet Order	Type of Action
Asiago	Italy/Austria	Warsaw	Livonia	Fleet LVN-PRU	Cutting the attacker’s support
Axis	Germany/Italy	Piedmont	Irish Sea	Fleet IRI C Army LVP-PIE	Convoying the attacking army
British Somaliland	Italy/England	Ionian Sea	Ionian Sea	Fleet ION H	Participating in the battle
North Cape	England/Germany	Tyrrhenian Sea	Tyrrhenian Sea	Fleet TYS H	Participating in the battle
The Pyramids	France/Turkey	Albania	Adriatic Sea	Fleet ADR C Army VEN-ALB	Convoying the attacking army
Reindeer	Germany/Russia	Barents Sea	St. Petersburg (north coast)*	Fleet STP (nc) S Fleet NWY-BAR	Supporting the attacking unit
Yorktown	France/England	English Channel	English Channel	Fleet ENG H	Participating in the battle

*One minor note is that a few coastal provinces (Spain, St. Petersburg, and Bulgaria) have two separate coasts, which means that a fleet located in one of these provinces has a different set of adjacent provinces it can move into or support into, depending on which coast it’s located in. In the given battles, the English Fleet in St. Petersburg can only support an attack into the Barents Sea from its north coast, while an English Fleet in Spain can support an attack into Portugal from either coast.

The final step is to arrange all 21 historical battles into a single timeline, sorting by date:

The first letters of the English Fleet locations spell out the cluephrase TREATIES IN CALVIN'S CITY. John Calvin worked in Geneva as a theologian during the Protestant Reformation, creating the Protestant denomination later named Calvinism. The famous treaties signed in Geneva are the GENEVA CONVENTIONS.

Author's Notes

NP: I originally came up with an idea for a Diplomacy-based metapuzzle. It was originally a pure meta where the feeder answers would clue pairs of DIplomacy provinces, and the solution was to take the unique province between each pair and extract the first letters. We testsolved this and similar pure meta ideas, but we eventually concluded that a pure meta Diplomacy puzzle was too basic.

Justin then came up with the main idea that would eventually be used in this puzzle. He suggested playing out an actual turn of Diplomacy, with one country’s units missing, so the answer would be extracted from the locations of those missing units. These locations would be determined by cluing historical battles whose participants matched those in the game. The missing unit would then help the winner of the historical battle win the Diplomacy battle. We then had the feeder answers being the names of these historical battles. We decided to have England as the missing country, and I came up with the historically thematic idea of forcing them to have only fleets and no armies, in order to constrain the number of possible locations from which the English units could influence a battle.

Testsolvers liked this new version of the puzzle, but forcing the feeder answers to be names of battle was too constraining, especially when trying to disguise it by using battles/operations with common words as names, such as Asiago, Magenta, and Compass. We thus changed this into a regular puzzle, using images to clue the historical battles instead. This allowed us to use a few battles named for their locations, as well as to add a fun image identification step instead of just giving the battle names directly. In addition, using 3 boards instead of 1 allowed for a long cluephrase which clued a very thematic answer.

Overall, although I was originally disappointed at having this puzzle demoted from a metapuzzle to a regular puzzle, I’m very happy with how it finally turned out.