GeoPulse — Triangulate the secret country

What is GeoPulse — Triangulate the secret country

GeoPulse hides one of forty-nine countries and gives you a blank world map and six pulses to find it. You type a country name — in English, Portuguese, Spanish or French, or just its two-letter code — and the game answers with three things: the great-circle distance in kilometres, an arrow along the bearing from your guess to the target, and a coloured echo, green under 1500 km, yellow under 5000 km and red beyond. The map fills with your pulses as you go, each a dot with a ring and a heading, so the shape of your search stays visible.

What matters is what those numbers do together. One distance puts the target somewhere on a circle drawn around your guess; a second distance, taken from a country far away, gives a second circle, and two circles meet in only two points. The arrows tell you which one to keep. That is trilateration, and a careful player rarely needs all six pulses: two well-chosen openings usually cut forty-nine candidates down to two or three. The score decays exponentially with the distance of your last pulse, so the final guess is never a probe: it is your answer, and the only one that counts.

How to play

1. Type a country and press Send Pulse. The autocomplete accepts names in four languages, and the two-letter ISO code works as well.
2. Each pulse returns the kilometres left, an arrow with one of eight compass directions, and an echo: green under 1500 km, yellow under 5000 km, red beyond.
3. You have six pulses and win only by naming the country: the two closest countries in the list sit 379 km apart, outside the 150 km winning radius.
4. The score comes from the last pulse alone — 1000 points at zero kilometres, 779 at one thousand, 472 at three thousand — so never waste the sixth guess.

Strategies that work

• Open with a country that splits the map by direction. From Kazakhstan, Norway, Greece, Turkey or France, the busiest combination of echo colour and arrow octant holds only seven of the other forty-eight countries. From Cuba, Jamaica or Venezuela it holds twenty-three, almost half the world in one bucket.
• Pick the second guess to cross the first, not to sit beside it. Argentina and France are one of the strongest pairs here: their rings and arrows sort the remaining forty-seven countries into twenty-nine groups, the largest with three. Two neighbouring guesses give near-identical circles and one wasted pulse.
• A green echo is rare and worth a lot: only fifty-five of the 1176 country pairs lie under 1500 km apart. Green usually leaves one or two candidates — Kenya and Ethiopia, Cuba and Jamaica, Japan and South Korea, Spain and Portugal. Stop widening the search and start naming neighbours.
• Nine hundred points needs a final distance under 421 km, and only three pairs are that close: United Kingdom and Ireland at 379 km, Cuba and Jamaica at 382, Spain and Portugal at 403. The Perfect Echo achievement, at 980 points, needs an outright win.
• Distances start from one point per country, so big countries behave like their centre: Russia's point is in Siberia at 61.5°N, 105°E. The arrow is rounded to 45°, so at ten thousand kilometres its octant still spans thousands — use it to pick between two crossings.

A little history

GeoPulse was written for puzzle-me.com and belongs to the family of distance-and-bearing geography puzzles that spread in 2022, after Wordle turned the one-guess daily puzzle into a habit. Those games usually show a country's silhouette and use distance as a hint. GeoPulse drops the silhouette and keeps only the measurement, which turns the puzzle into trilateration, the idea a satellite receiver uses to fix a position from its distances to known points. The radar vocabulary follows from that: you never see the target, you only measure how far away it answers.

Frequently asked questions