Block the Path: strategies to win

In Block the Path the fastest runner doesn’t necessarily win: the one who can count does. Every turn you choose between a step and a wall, and the right choice comes from comparing two numbers, your route and theirs. This guide shows how to do it, what a wall is really worth, how to defend yourself and how to play the endgame.

Reading the board

To talk about specific squares we need names. In this guide the columns run from a to i, left to right, and the rows from 1 to 9 starting from your side: your pawn starts on e1 and has to reach row 9, your opponent’s starts on e9 and has to reach row 1. It is the same notation players of the board game use.

A wall goes on one of the 64 inner crossings of the board, horizontal or vertical: 128 possible placements in all, minus those already taken or not allowed. That is a lot, which is why you need a way to choose: almost all of them are useless, and some hurt you more than your opponent.

The word we will use most is route: the smallest number of steps a pawn needs to reach its goal, taking every wall on the board into account. It is not the distance as the crow flies. A pawn two rows from home, shut in a pocket of walls, can have a route ten steps long.

The count that decides the game

Set the walls aside for a moment and imagine neither player has any left. The game is then a race, and the result is known in advance:

The player to move wins the race if their route is no longer than the other’s.

Example: it is your turn, you need 6 steps and your opponent needs 6. You arrive on your sixth step, while they still need one more. If you needed 7, they would get there first. Having the move is worth exactly one step, which is why at the start, with 8 steps each, whoever moves first has the edge.

With walls in play the count is still the starting point: redo it for both players every turn, because every move changes it. If the count says you win and your opponent has no walls left, all you have to do is run. If it says you lose, you need a wall, but not just any wall.

What a wall is worth

A wall always costs a turn: while you place it, you don’t move. Its real value, which we will call its yield, works out like this:

yield = steps added to their route − steps added to yours − 1

The −1 is the turn you spent. A wall that makes your opponent’s route one step longer has a yield of zero: it is as if you had both lost a step, and nothing has changed. A lone wall in the middle of the board, right in front of a pawn, almost always ends up like that: they step sideways and carry on.

The walls that really pay are the ones that force the opponent to go backwards. Every step backwards counts twice, because it then has to be won back. And to turn a pawn around with a single wall, the pocket must already be nearly closed: by the edge of the board, by a wall that is already there, or by both.

Before the blue wall, orange needs 4 steps (the dotted line). After it, its shortest route is 8.

In the example the orange pawn is on a5, running down the edge: it needs 4 steps. A vertical wall between columns b and c, placed earlier, doesn’t seem to bother it. But a horizontal wall below a5 and b5 closes the pocket: to get out it has to go back up to a6, across to c6 and only then down. The route goes from 4 steps to 8: the wall adds 4 and, if your own pawn is far away, yields 3. A single wall like that can turn a lost race around.

The practical way to find one: follow your opponent’s shortest route and ask where it squeezes through a narrow spot, between a wall and the edge or between two walls. That is where one wall cuts off the good route and sends them the long way round.

Hidden costs

Walls don’t belong to anyone: they block whoever passes that way. The yield formula has a term almost everybody forgets, the steps the wall adds to your route. It happens mostly in the middle of the board, when the two pawns cross paths and use the same corridors.

So before you confirm a wall, redo the whole count: their route after the wall, your route after the wall, and who will have the move. A wall that adds 3 steps to theirs and 2 to yours yields nothing. Worse, a wall placed to lengthen their route can later become the very piece they need to close a pocket around you.

The opening: move forward, don’t rush

The first moves are almost always steps forward. At this stage both routes are long and open, and a wall can’t yet turn anybody around: it adds one step, yield zero. A sidestep in the first few moves is considered a mistake, because it gives the opponent room to push you back later.

The classic opening mistake is a wall dropped right in front of the opponent’s pawn. It looks aggressive, but they step aside, you have lost a turn, and that wall stays there, shaping a corridor that may end up helping them.

In the board game made famous by Quoridor, experienced players have given names to the most studied openings. Two are worth knowing here too:

• The Shiller: three steps forward, then a vertical wall next to your own route, in your half of the board. It doesn’t slow the opponent down right away: it starts shaping your route before they get the chance to.
• The Sidewall: after the opponent’s first step, a vertical wall right next to their pawn. It pushes them towards one side without putting obstacles on your route. If it is played against you, don’t chase: the recommended answer is a horizontal wall that starts closing off the side they are pushing you towards.

Behind both lies the same idea, the most useful principle in the whole game: make your own routes shorter and your opponent’s longer, with walls as well as with steps.

Midgame: guard your back

The biggest danger isn’t a wall in front of you but open space behind you. If you are running along one side and there is still an open route behind you, your opponent can close the way ahead with a wall or two: your shortest route then runs back through that gap, and you have to retreat several squares. Leaving your back open in the middle of the game usually loses.

The defence feels backwards: use your walls for your own pawn. A wall placed beside or behind you, shutting off the long way round, slows nobody down right now, but it means your route only goes one way: forward. Experienced players spend a good share of their walls like this, not in front of the opponent.

Two signs that it is time to do it:

• your route squeezes between a wall and the edge, or between two walls: a single wall from your opponent would be enough to close it;
• behind or beside you there is an open passage that would become your shortest route if the way ahead were closed.

The reverse holds too: a wide route, with several paths of the same length, is hard to lengthen. Before you take a step, ask whether the square you are moving to leaves you one way out or several.

The jump and parity

When the two pawns are on the same column facing each other, sooner or later one of them will be able to jump the other and gain a step. Who gets the jump is decided by counting the free squares between the two pawns when it is your turn:

• if the number is even, the jump will be yours;
• if it is odd, it will be theirs.

Example: you are on e4, they are on e7, and it is your turn. There are two free squares in between, e5 and e6. You move to e5, they move to e6, and now they are the one standing right in front of you: you jump to e7. With three free squares it would have gone the other way.

If parity is against you, you can change it by spending a turn without getting closer: a sidestep, or a wall you needed anyway. Remember too that if there is a wall or the edge behind you, your opponent’s jump becomes diagonal: before you stop in front of them, check that the diagonal doesn’t land them right on the route they were looking for.

Walls in hand and the endgame

The endgame is usually said to start when one player has fewer than three walls left. From then on what matters most is the difference in walls: whoever has more can afford to wait, and whoever has fewer has to hope the step count is enough.

The reason is simple. If you lengthen your opponent’s route with a wall and they still have a wall to answer with, they can often return the favour and the count is level again. But once they have run out, every good wall you place is a clean gain, and all they can do is run.

When only you have walls left, the race works out like this: it is your turn and your route is a few steps longer than theirs; call that the gap. You win if the yields of the walls you manage to place add up to at least the gap. If you need 7 steps and they need 4, the gap is 3, and a single wall like the one in the example above, yielding 3, is enough to win the race.

That is why it pays to reach the end with two or three walls still in hand, and why a wall spent early for zero yield is a wall you won’t have at the very moment it would be worth the most.

Against the Pocket Games bot

The bot’s three levels play differently, and each one is beaten differently:

The hard bot in particular sees only one reply from you after its own move. A trap that takes two walls in a row, the first one harmless-looking and the second one closing the pocket, only becomes visible to it once it is already inside.

The most common mistakes

• The wall in front of the pawn, early on. Zero yield: they step aside and you have lost a turn.
• Counting only the opponent’s route. A wall that also lengthens yours yields less than it looks, sometimes nothing.
• Running out of walls first. From then on your opponent decides where you go and you can no longer answer.
• Running with your back open. One wall in front is enough to send you back half the board.
• Placing walls when the race is already won. If the count says you win and they have no walls, every wall is a turn given away.
• Closing in without counting parity. The jump is worth a step, which is often the whole game.

In practice, every turn

1. Count your route, theirs, and who has the move.
2. If you win the race and they have no walls to change it, run.
3. If you lose it, look for the wall with the highest yield: where their route squeezes through, near the edge or a wall, ideally one that turns them around.
4. If no wall yields more than zero, take a step and keep the wall.
5. Check your back: if a single wall could send you backwards, close that passage yourself before they do.

The full rules and the frequently asked questions are on the Block the Path page, and you can play right away in your browser, against the bot or with two players on the same phone. More guides are on the guides page.