What is Yin-Yang?
Yin-Yang is a black and white logic puzzle played on a square grid. Some cells are given as black or white clues, and your job is to colour every empty cell so the finished board obeys three clean rules.
All black cells must form one orthogonally connected group, all white cells must form one orthogonally connected group, and no 2x2 area may be entirely black or entirely white. This online Yin-Yang puzzle game gives you six grid sizes, three difficulty levels, hints, checking, undo and a uniqueness-tested puzzle generator.
- Click or tap a cell to cycle it through black, white and empty.
- Keep every black cell connected through edges.
- Keep every white cell connected through edges.
- Avoid every 2x2 square of one colour.
- Each generated puzzle is checked for one unique solution.
How to play Yin-Yang online
Start with the fixed black and white clues. A useful first scan is every 2x2 square: if three cells in a 2x2 are already the same colour, the fourth cell must be the other colour.
Then look at connectivity. A colour that is about to split into two separate islands usually forces a bridge. A colour trapped behind the opposite colour is a warning sign, because the final Yin-Yang solution must leave both colours as single connected areas.
- Use Black and White when you want to place a specific colour.
- Use Check for feedback without revealing the whole solution.
- Use Hint to add one correct cell from the unique solution.
- Use Solution to study the complete answer.
- Change size or difficulty at any time for a fresh puzzle.
Yin-Yang rules
The rules are short, which is why Yin-Yang is such a good logic game for beginners. You do not need arithmetic, symbols or regional cages. Every deduction comes from connected black cells, connected white cells and the 2x2 rule.
The 2x2 rule prevents large solid blocks, while the connectivity rules prevent isolated spots and cut-off regions. Together they create a puzzle that feels simple at first and surprisingly strategic as the grid grows.
- Black cells connect only up, down, left and right.
- White cells connect only up, down, left and right.
- Diagonal touching does not connect a colour group.
- A 2x2 block of four black cells is illegal.
- A 2x2 block of four white cells is illegal.
Yin-Yang strategy tips
The strongest Yin-Yang strategy is to combine local and global thinking. Local deductions come from 2x2 blocks, edges and corners. Global deductions come from asking whether a colour can still connect to the rest of itself.
When a puzzle feels stuck, trace each colour as if it were a path of territory. If a move would seal off one black cell or one white cell forever, that move cannot be part of the solution.
- Finish any 2x2 square where three cells already match.
- Watch corners because they have fewer escape routes.
- Avoid making a single isolated cell of either colour.
- Use the edge of the grid to spot forced connections.
- Do not guess if a connectivity bridge is available.
Grid sizes and difficulty
This Yin-Yang game includes 6x6, 7x7, 8x8, 9x9, 10x10 and 11x11 grids. Smaller grids are best for learning the rules. Larger boards create longer connection questions and more subtle 2x2 traps.
Easy puzzles keep more starting clues on the board. Medium puzzles remove more information, and hard puzzles ask you to hold several connectivity ideas at once. The generator only accepts a puzzle when the solver confirms a single solution, which is expected for a fair logic puzzle.
The diagonal rule that cracks Yin-Yang
Beyond the no-2x2 rule, Yin-Yang hides a second, more powerful pattern: no 2x2 may be a checkerboard of alternating colours either. A checkerboard would force black and white to cross at that corner, and because each colour connects only up, down, left and right, a crossing always splits one colour into two pieces. So in every 2x2 the two cells of each colour must sit side by side, never on a diagonal.
This gives a deduction that solves long stretches at once. When two cells of the same colour touch only at a corner, look at the two cells wedged between them. They cannot both take the opposite colour, or you would build that forbidden checkerboard. At least one of them must match, opening the only route the colour has to stay connected.
- A 2x2 of four identical cells is illegal (the basic rule).
- A 2x2 checkerboard of alternating colours is also illegal.
- Valid 2x2 squares keep their matching cells adjacent, not diagonal.
- Two same-colour cells touching at a corner force at least one connecting cell to match.
- Spotting a near-checkerboard often forces the fourth cell instantly.
No sealed pockets: reading edges and corners
Because both colours must end up as one connected group, neither colour can wall off a pocket of the other. The edges and corners are where this bites hardest: a corner cell has only two neighbours, so a single wrong colour there can trap its opposite with no way out.
Before committing a cell, trace the opposite colour around it. If your move would seal even one cell of the other colour against the wall with no orthogonal exit, the move is wrong. Reading the rim of the grid first usually forces several border cells and gives the interior something to connect to.
- Corners have only two neighbours, so they force quickly.
- Never trap a single opposite-colour cell with no orthogonal exit.
- A colour hugging the edge must eventually turn inward to reconnect.
- Solve the border before the centre when a board feels open.
- A pocket that cannot reach the rest of its colour means an earlier move was wrong.
Yin-Yang and other shading puzzles
Yin-Yang belongs to the family of shading logic puzzles, where you colour cells under connectivity rules instead of writing numbers. If you enjoy it, the same instincts carry over to Nurikabe, where one connected sea must avoid 2x2 pools, and to Hitori, where shaded cells may never touch while the unshaded cells stay connected.
What makes Yin-Yang especially clean is its symmetry: both colours follow the exact same rules, so there is no background colour. That balance is where the name comes from, and it is why a single misplaced cell is so often visible at once as a broken connection or an illegal block.