Sudoku for absolute beginners
One rule, the scanning habit that applies it, and the two patterns that finish your first grid without a single guess.
8 min read
Back home
Somebody explains the method
Twenty pieces on how these puzzles actually come apart, written by the people who wrote the generators. Ten cover the method for a specific board; the other ten go further into technique, probability and the reasons some puzzles are harder than they look.
20
guides
Start here
One guide for each of the ten puzzles
Minesweeper opening patterns
How to read the edge of an open region, plus the 1-1 and 1-2-1 shapes drawn out cell by cell.
7 min read
Nonogram solving basics
What the clue numbers mean, how overlap hands you free squares, and why marking blanks matters as much as filling.
8 min read
Lights Out is parity, not luck
Why click order never matters, why pressing twice is the same as never pressing, and how to chase the lights downward.
7 min read
Sokoban: planning and deadlocks
The positions a crate can never come back from, and why solving backwards from the marks is faster than pushing.
9 min read
A method for the sliding puzzle
Solve it in layers, learn the three-tile rotation, and stop destroying the row you have just finished.
8 min read
Tower of Hanoi and recursion
Why the answer is exactly two to the n minus one, and the one-line rule that plays it perfectly.
7 min read
Finding words faster
Scan by first letter, start with the long words and the rare ones, and stop re-reading the same corner.
6 min read
Memory Match without trying to remember everything
Why tracking the whole deck fails, how to chunk a grid into corners, and the turn order that turns one lucky flip into two pairs.
6 min read
Connect Four and the centre column
Why the middle column is worth more than the rest of the board put together, and how a double threat ends a game early.
8 min read
Going deeper
Technique, proofs and the puzzles themselves
Four Sudoku techniques past the beginner stage
Naked and hidden pairs, pointing sets, box-line reduction and the X-wing — each drawn out, and all the same idea underneath.
10 min read
When Minesweeper makes you guess
Working out which cell is safest, why the mine counter is a clue, and how to pick a guess that teaches you something.
8 min read
Nonograms: the harder line techniques
How a single blank cuts a line into shorter ones, pinning a run against an edge, and knowing when a line is finished.
9 min read
What makes a Sokoban level hard
Why crate count measures nothing, how forced ordering creates depth, and why machines find this puzzle difficult too.
8 min read
Half of all sliding puzzles cannot be solved
The inversion count that decides whether a board has an answer, and the prize that was offered for an impossible one.
8 min read
Where these ten puzzles came from
Short histories of all ten: who made them, when, and which of the widely repeated origin stories are simply not true.
9 min read
How we prove a board is fair before you see it
Counting Sudoku solutions, shuffling by legal moves, solving crate levels by machine, and why randomness needs care.
9 min read
Playing every puzzle from the keyboard
The complete key map for all ten boards, plus how the site handles screen readers, reduced motion, colour and zoom.
7 min read
What actually makes a puzzle hard
Branching, depth, reversibility and forced guessing — the four properties behind difficulty, and why labels are estimates.
8 min read
Puzzles without the streak
What the usual retention machinery does, why none of it is here, and a practical way to handle being stuck.
6 min read