Reference
Sokoban glossary
Sokoban has its own vocabulary, and Sokoban-Lettres adds some of its own. This glossary gathers the terms used in the game and in this guide, with their exact meaning in Sokoban-Lettres where it differs from classic Sokoban.
The parts of the grid
- Sokko
- The character you move. It walks on free squares and pushes boxes; it can neither pull them nor go through a wall.
- Box
- A movable block carrying a letter. It moves one square when Sokko pushes it and the square behind it is free.
- Target
- A destination square. In Sokoban-Lettres, targets always form one continuous horizontal line, and each one waits for a specific letter.
- Target word
- The word spelled by the targets, read from left to right. Putting each box on a target is not enough: the letters must be in order.
- Wall
- A square that neither Sokko nor boxes can enter. The edge of the grid behaves like a wall.
- Corridor
- A passage one square wide. A box that enters it can no longer be walked around.
- Turning area
- A space wide enough for Sokko to get round to the other side of a box. These areas often decide the order in which letters can be placed.
Actions and how they are counted
- Move
- Every step Sokko takes, whether or not it pushes a box. The number of moves decides the quality of letters and the ranking of players.
- Push
- A move that shifts a box. The game’s solver looks for the solutions with the fewest pushes.
- Undo
- Taking back the last move. The game keeps up to 200 moves; each undo costs a life.
- Reset
- Putting the grid back to its starting state. It is free and also resets the move counter and the timer.
Lost positions
- Deadlock, or dead square
- A position from which a box can no longer reach its target. The game detects corners, walls without a target and two-by-two squares; see spotting and avoiding deadlocks.
- Corner
- A square bounded by a wall, or the edge, in both directions. A box that enters one without finding its target there is lost.
- Two-by-two square
- Four squares in a block, all taken by walls or boxes, which lock each other in place.
- Freeze
- Two or more boxes blocking each other along a wall without forming a corner. The game does not detect this case.
Measuring performance
- Par
- A level’s reference number of moves, worked out from the solution found by the solver. It is a benchmark, not an impossible record.
- Gold, silver and bronze letters
- The quality of the letter earned by finishing a level: gold at no more than 125% of par, silver at no more than 150%, bronze beyond that.
- Collection
- All the letters earned during the month. It is complete when it covers the whole alphabet of the language being played.
- Score
- The ranking criterion: the number of moves first, then time to separate two players on equal moves. Details are in scoring and par.
Modes and time
- Adventure
- Progress through chapters, where each level unlocks when the previous one is finished.
- Daily Challenge
- One grid shared by every player for a given date, with an archive for replaying past days.
- Streak
- The number of consecutive days on which the Daily Challenge was completed. A broken streak can sometimes be recovered.
- Life
- The resource spent to undo or ask for a hint. Players receive three a day.
- Hint
- Help that points out a box, its target, or the route to push it there; see hints and lives.
- Difficulty modes
- Discovery, Scout, Investigator and Oracle progressively hide the letters on boxes and targets; see the difficulty modes.
Behind the scenes
- Solver
- The program that solves each level before it is published. Sokoban-Lettres uses a search algorithm called IDA*.
- Seed
- The number which, combined with the word, fully determines a generated grid. The same seed and word always produce the same level.
- Chapter
- A group of Adventure levels. Generation settings get stricter from one chapter to the next; see how levels are generated.