The rules
Chain countries by land border, with no repeats.
Borderline is a survival chain: the map starts blank and fills only with the places you name. There is no daily puzzle and no timer. You can start a fresh run whenever you like, and an in-progress run is saved so a refresh picks up where you left off.
- You are dealt a start. Each run begins with a random country, highlighted on the map as the live country.
- Chain by land border. Your next answer must share a land border with the live country. A correct answer joins the chain and becomes the new live country.
- No repeats. Each country can appear in the chain once. Naming one you already used ends the run.
- Dead ends become jumps. When the live country has no unused borders left, the only legal answer is the single closest unused country by straight-line distance. Anything else ends the run.
- Score is chain length. The Exits counter shows how many unused borders the live country has, and your best chain for each mode is saved on your device.
Borders come from the map geometry itself, so sovereign overseas territory counts: France borders Brazil and Suriname through French Guiana. Dependencies such as Greenland, Puerto Rico, and Hong Kong are not in the playable pool. Common alternate names are accepted (UK, USA, Ivory Coast, DRC, Burma), and text that matches nothing in the pool simply does not submit, so a typo will not kill your run.
A worked example chain
Say the game deals Spain. A strong opening: Spain to France, because France is one of the best-connected countries on the map. From France you could stay in Europe, or use the map geometry: France to Brazil is legal through French Guiana. Then Brazil to Bolivia, Bolivia to Argentina, Argentina to Chile.
Now the trap: Chile only borders Peru, Bolivia, and Argentina. Bolivia and Argentina are already used, so if you take Chile to Peru and later come back down the coast, you can run out of exits entirely. When that happens the run does not end; the game tells you to name the closest unused country instead, and one precise jump keeps the chain alive.
Countries mode and states mode
Countries— the world map with sovereign countries and their land borders. Island nations with no land borders are in the pool but can only enter or leave the chain through closest-country jumps.
States— the same chain rule with the 50 U.S. states. Only the 50 states are playable; DC and territories are excluded. Two-letter abbreviations work as answers. Each mode keeps its own saved run and its own best score, so you can switch back and forth without losing progress.
Strategy tips
- Plan toward high-degree hubs. Russia, China, Brazil, France, Germany, and Turkey each touch many countries, so routing through them keeps your options wide open for the whole run.
- Do not burn a hub’s neighbors before you get there. If you sweep through Central Asia early, arriving in Russia later is far less valuable because its exits are already used.
- Avoid pocketing yourself. Peninsulas and one-border countries (Portugal, Denmark, South Korea, Qatar, The Gambia) are safe to visit early but dangerous late, because they spend an exit and give little back.
- Watch the Exits counter before every answer. Walking into a country with one unused border is fine only if you are happy to jump afterward.
- In jump mode, think nearest, not most famous. The legal jump is the single closest unused country by straight-line distance, so from a Mediterranean dead end the answer is more likely Malta or Cyprus than anything big.
- In States mode, the same logic applies: Missouri and Tennessee each border eight states and make excellent hubs, while New England corners like Maine (one border) can strand you.
FAQ
How does the country border chain work in Borderline?
The game deals you a random starting country. Every answer after that must be a country that shares a land border with the current highlighted country, and you cannot repeat a country already in your chain. Each correct answer becomes the new live country and adds one to your score.
What ends a Borderline run?
Naming a country that does not border the live country, repeating a country already in your chain, or naming the wrong country during a closest-country jump. Typos and names outside the pool simply do not submit, so they cannot end your run.
What happens when my chain hits a dead end?
A dead end does not end the run. When the live country has no unused bordering countries left, the game switches to jump mode: the only legal next answer is the single closest unused country by straight-line distance. Name it and the chain continues from there.
Can island nations like Japan or Iceland be part of the chain?
Yes, but only through jump mode. Island nations have no land borders, so they are never a legal border move. You can land on one when it is the closest unused country during a jump, and leaving it is always another jump.
Do overseas territories count as land borders?
Sovereign land borders count because the game reads borders straight off the map geometry. France borders Brazil and Suriname through French Guiana, for example. Dependencies and non-sovereign territories such as Greenland, Puerto Rico, and Hong Kong are not in the playable pool.
Is there a U.S. states version of Borderline?
Yes. States mode uses the same chain rule with the 50 U.S. states: every answer must border the previous state, with no repeats. DC and territories are excluded, and each mode keeps its own best score and its own in-progress run.