How to solve a Survivor block puzzle

In South Pacific (season 23), Upolu got to the block puzzle first. Then Savaii caught up. Savaii finished their puzzle just ahead of Upolu and won reward and immunity.

That is the block puzzle in one story. A head start helps, but the race is decided at the frame, by the team with a plan.

We found three US episodes with a block puzzle, from 2004 to 2019. This guide shows how the puzzle works, teaches a method you can drill, and looks at what the winners did. Every board on this page is live.

How a block puzzle works

A block puzzle is a frame full of wooden blocks in different sizes. There are only two empty squares. One big block, the crate, has to come out through a gap in the bottom of the frame. You can slide blocks, but you can’t lift them.

On the show, the puzzle has been giant. In South Pacific, four tribe members worked it together. In Edge of Extinction (season 38), six did. In All-Stars (season 8), each player worked their own puzzle, and the piece that came out held a knife.

The puzzle is also called Klotski. Our game uses the usual frame, four squares wide and five tall. It holds the crate, four tall blocks, one wide block, and four small ones.

In our game, moving one block counts as one move, however far it slides. It still counts as one if it turns a corner. That is the usual way to count Klotski moves.

Step 1: Clear the road

The crate is two squares wide. To move down, it needs both squares under it to be empty. So your first job is to clear the blocks in its way.

Once the road is clear, the crate can slide all the way to the gap in one move.

Step 2: Swap the crate past a tall block

Most of the time, tall blocks stand on both sides of the crate. The crate can’t go down until it moves over. It can’t move over until a tall block gets out of its way.

The fix is a swap. Slide the crate down a row. That opens room above it for a tall block to climb up beside it. Now the crate can step sideways into the space the tall block left.

You will use this swap again and again. Watch for it in the “Show me” demo below.

Step 3: Keep your two empty squares together

You only have two empty squares. A small block can move into either one. A tall block can move up or down into one, but to move sideways it needs both, one above the other. A wide block is the other way around. The crate always needs both, lined up on the side it’s moving toward.

Before each move, ask where the empty squares will end up. If a move splits them apart, the next big block may get stuck. Small blocks are the easiest way to move the empty squares around.

Step 4: Look for long slides

A long slide is still one move. So is a slide around a corner. When a block has room, take it as far as it needs to go in one go.

In Practice mode, each hint shows the next move of a shortest solution. The results screen tells you the fewest moves your board can take, so you can see how close you came.

The classic board

This is the usual starting layout. Martin Gardner published an 81-move solution in Scientific American in February 1964. Wikipedia says computers have shown that 81 is the fewest moves possible. Our own solver agrees.

Our solver also counted every position you can reach from this start. There are 25,955 of them.

What the winners did

They didn’t quit when they were behind

In South Pacific, Upolu reached the puzzle first. Savaii kept working and caught them. A lead into the puzzle is only a head start.

They listened to one voice

In Edge of Extinction, Kama got ahead after Manu struggled on the balance beam. Then Julia called the moves, and Kama solved the puzzle first. Six people pushing blocks need one plan.

They kept their hands moving

In All-Stars, Rob solved his puzzle quickly. He got the knife out, cut the rope, raised his flag, and won immunity.

If you’re the caller

These tips are our own advice, not rules from the show.

• Name the block, then the way it goes: “C, up.” Our game puts a letter on every block for this reason.
• After each move, say where the crate is now.
• Call the swap out loud before you start it, so everyone knows the next three moves.

A practice plan

1. Start on Easy in Practice mode. Use hints until the swap feels natural.
2. Switch to Challenge and work up through Easy, Medium, and Hard. Try to match the fewest moves.
3. Play the Daily. Everyone gets the same board, and only your first solve counts.
4. When you’re ready, take on the classic. Then press “Show me” above and compare.

Play the block puzzle

Why you should put the blocks back carefully

If you practice on a real puzzle and the blocks fall out, put them back the way they started. Don’t just drop them in. We tested 100 random layouts of the classic blocks. In 35 of them, the crate could never get out, no matter what you did. Every board in our game is checked by the solver first, so it can always be solved.