Sokoban · sixteen rooms · no clock
Block Push
You can shove a crate and you can never drag it back. Sixteen rooms have been built around that one rule, and every one of them is proved finishable before it goes in. Take as long as you like. Undo costs nothing.
Block Push
Walk into a crate to push it one square. Get every crate onto a goal. There is no clock and no penalty for thinking, so read the room before you move.
- W A S D or Arrows walk, and push what is in front of you
- U undo one move · unlimited
- R restart the room
- L level board
- P or Escape pause
- Enter begin
Held
The room is exactly as you left it. Nothing has moved and nothing will.
- U undo
- R restart the room
- L level board
Room clear
0Par 0 · Best 0
Every crate is home.
| Input | What it does |
|---|---|
| Arrows / W A S D | walk, and push whatever is in front of you |
| U | undo one move, as many times as you want |
| R | restart the current room |
| L | open the level board and pick an unlocked room |
| P or Escape | pause · Enter start or continue |
Push, never pull
The whole game is one rule. Walk into a crate and it slides one square away from you, provided the square behind it is empty. Walk into a wall and nothing happens. There is no push button and no way to drag anything back towards you, so where you stand matters as much as which way you face: the same crate in the same room is a different problem from the other side.
Room one is two moves long. It is not there to be difficult; it is there so you can feel the difference between walking and pushing before the game starts asking questions. Later you will spend two moves on your feet for every one you spend on a crate. Most of Sokoban is walking.
Reading a room before you touch anything
Stand still for five seconds when a new room appears. Find every goal first — the dim green sockets set into the floor — and work out which side a crate has to arrive from. A socket in a corner only accepts a crate from two of its four sides, and if both are walled off that goal needs a different crate than the nearest one, which usually means the delivery order is not the one you assumed.
Then look for the narrow bits: one-square doorways, alcoves, anything only one crate can pass at a time. That is where order matters. If two crates have to use the same doorway, the one that ends up furthest from the door goes first, every time, because the second crate needs somewhere to stand while it waits.
The mistake that ends more levels than any other
Pushing a crate flat against a wall is the classic way to lose. A crate with a wall on one side can still be shoved along it, but only in one direction and only while you can get behind it. A crate with walls on two sides — a corner — is finished unless it is already on a goal.
Room five is built around this. The crate starts in a small room with a single doorway on the right-hand wall. Shove it against the top wall first and the room is thrown away; ease it right, then down, and the door is in front of you. U steps back one move and can be pressed as often as you like.
What par means, and why moves are the score
Every room has a par, and par is the fewest moves the room can be finished in. It was not guessed at. Each of the sixteen was run through a search that walks every reachable position on the board and reports the shortest solution it finds, so matching par is a genuinely good result and beating it is not possible.
Your score is your running total of moves across every room you clear in one session, so lower is better. If your pushes are near par but your moves are far above it, you are taking the long way round; if your pushes are well over par, you are moving crates in the wrong order and no amount of walking will save you.
The best figure in the corner of the screen is the fewest moves recorded on the room you are standing in, kept in this browser. It updates the moment you beat it, so a room you have already cleared is still worth going back to.
Questions that turn up around room nine
Is there a timer?
No. Nothing here measures how long you take. Sit and stare at a room for as long as you like. The only number that gets worse is your move count, and only when you actually move.
Can I make a level impossible to finish?
Yes, and fairly easily. Push a crate into a corner that is not a goal and it is stuck there for good, and if a goal needed that crate the level is over. Undo is unlimited, which is the whole reason the mistake is survivable: press U and the last move comes back. If you have made a real mess, R puts the room back exactly as it started and resets both counters, so a restart never costs you a bad move count.
What does the green crate mean?
A crate turns green the moment it is sitting on a goal, and the level ends when every crate is green. Nothing locks. A green crate can still be pushed off if you need the space, and it goes back to amber the instant it leaves the socket.
What is par?
Par is the fewest moves a room can be finished in. It was not guessed: each level was run through a search that walks every reachable position and reports the shortest solution it finds, so par is a real target rather than an estimate. Matching par is a very good score.
Do I have to finish all sixteen rooms in one sitting?
No. The fewest moves you have managed on each room is kept separately in this browser, so you can chip away at the set across as many sessions as you like. Only the running session total starts again when you reload.
Why the boards had to be proved, not tested
I built this because Sokoban is the purest puzzle going: no randomness, no clock, no hidden information, one rule. Everything hard about it comes from the shape of the room, which means a level that cannot be finished is not a challenge but a broken one, and the player cannot tell the difference except by wasting twenty minutes. So all sixteen were checked by machine before shipping.
The other decision was undo. A puzzle you are frightened to experiment in is a puzzle you stop playing, so undo is free, unlimited, and rewinds the counters along with the crate.