GeoVault — Country Deduction Puzzle

What is GeoVault — Country Deduction Puzzle

GeoVault hides a four-country combination behind a lock. Order matters, no country repeats, and you have eight attempts. Fill the four slots from the list of 77 countries, submit, and each slot answers back on its own: green means the right country in the right place, yellow means the country belongs in the code but sits in the wrong slot, and white means it is not in the code at all. Because the feedback comes slot by slot, not as a blind count, every guess is four separate experiments, and a single yellow narrows that country to one of three positions.

Four slots drawn from 77 countries give more than 32 million ordered combinations, so brute force is hopeless in eight tries. That is what the clues are for. One is already open before you start, and it always tells you how many of the four come from one named continent; another unlocks after every guess that is not your last. They talk about starting letters, exact letter counts, shared borders, island nations and vowels, and each one is stated either about a specific slot or about the code as a whole. The vault opens the moment all four slots turn green.

How to play

1. Press Play, tap a slot, type in the search box and pick a country; the cursor moves to the next empty slot.
2. Fill the four slots with four different countries and press Submit Guess; each slot then turns green, yellow or white on its own.
3. Read the clue that unlocks under the board, cross out what it rules out, and aim the next guess at untested positions.
4. Turn all four slots green within eight attempts; if the eighth fails, the code is revealed and the round still counts.

Strategies that work

• A green slot is worth 150 points on every guess it appears in, not only the one where you found it. Leave a confirmed country in place until the end: you collect those 150 again each turn and the other three slots stay free for testing.
• The letter clues are not scattered at random: over a full round you get exactly one about each of the four slots. Two give a starting letter, two the length of the name, one exact and the other only odd or even. Note which slot each names.
• The starting letter is the strongest clue. Only two of the 77 countries begin with J, and D, H, K and Y have one each. If slot 3 starts with J, you choose between Japan and Jordan. The crowded letters are C, I and S.
• The free continent clue is a counting constraint, not a hint about one country. Europe supplies 30 of the 77 countries and Asia 22, so “exactly one is from Europe” removes far more than it confirms. Only ten countries in the whole pool are island nations.
• An extra attempt costs 200 points of unused-attempt bonus plus 80 for the clue it unlocks, while two confirmed greens already return 300 a turn. Spend it testing four different initials or four different continents at once, never on a country that already came back white.

A little history

GeoVault belongs to the Mastermind family. Bulls and cows, a pencil-and-paper game much older than the box, became the coloured-peg game Mastermind in the early 1970s, and the idea has barely changed: a hidden row, narrowed by the answer it gives back. What changes here is the alphabet of the pieces. Instead of six colours there are 77 countries, and a country carries properties a colour does not have — a continent, a name of a given length and initial, borders with neighbours. The clue track does the heavy lifting.

Frequently asked questions