Sokoban Solutions: Push Boxes to Goals

The single most powerful Sokoban technique is working backwards from the solution. Instead of asking "where can I push this box," ask "what position does this box need to be in, and what must be true for me to push it there?" This reverse analysis reveals moves you would never find by pushing forward. Start by identifying which goal positions are the most constrained - the ones in corners, against walls, or in narrow corridors. These boxes must be placed first because they have the fewest possible approach paths. Work out how each constrained box gets to its goal, then figure out the order. Backwards thinking also reveals which boxes should be placed last. Boxes that go to central, open goal positions have many possible paths and can be adjusted later. Constrained boxes have one or two valid paths and must be solved first to avoid blocking other solutions.

A deadlock occurs when a box is pushed into a position from which it can never reach any goal. Deadlocks are the most common reason players get stuck. Learning to recognize them before they happen is the most important skill in Sokoban. The simplest deadlock is a box pushed into a corner that is not a goal position. Since you can only push and not pull, a box in a corner is permanently stuck. Similarly, a box against a wall between two other boxes against the same wall creates a frozen cluster that cannot be moved. A more subtle deadlock happens when two boxes are pushed side by side against a wall. Neither can be moved forward along the wall because the other box blocks the approach. Always check whether a push creates a frozen pattern before committing to it.

In corridors (narrow passages one or two tiles wide), boxes can only be pushed in one direction along the corridor. Once a box enters a corridor, it must be pushed all the way through or it blocks the corridor. Plan corridor pushes carefully before committing. The "man behind" principle means you need to position yourself behind a box to push it. Sometimes you need to navigate around the box to approach it from the correct side. This maneuvering is often the hardest part of Sokoban and requires careful sequencing of moves. Learn to recognize common pushing patterns: the L-push (navigating a box around a corner), the zigzag (pushing a box along an alternating path), and the relay (using one box to create a path for another). These patterns appear in nearly every Sokoban level.

Before making your first move, spend time analyzing the level. Count the boxes and goals, identify the corridors and open areas, and map out the general flow of boxes from their starting positions to their goals. This "big picture" view prevents wasted moves. Look for boxes that are already near their goals and figure out if they can be placed early. Sometimes a single box is already one push away from its goal. Clear these easy placements first, but check that doing so does not block access to other goals. Identify the "key" box - the one whose solution path constrains all others. In many levels, one box must travel through a bottleneck area, and all other box movements must be coordinated around this critical path. Solving the key box first often makes the rest of the level straightforward.