Pair cap
Two matching neighbors force the open cell beside them to the opposite digit.
Prove every 0 and 1 across a 90-level campaign. Daily and seeded Practice stay repeatable, while verified hints explain one forced next move from the current state instead of exposing the full answer.
6×6–12×12 can fall back to exact continuation proof. 14×14 deliberately stays on the fast named-deduction chain rather than pretending an expensive answer reveal is a logical hint.
Fill the grid without guessing. The V0.230 Logic Lens explains named deductions, checks the exact constraint model on demand, and keeps help-assisted runs separate from clean solves.
Every row and column has an equal number of 0s and 1s.
Binary Puzzle
The live lens uses only the three Binary Puzzle rules for local deductions. “Verify state” additionally runs the independent full constraint model and reports whether the current entries still admit the unique board.
The next named deduction will appear here without pretending an answer reveal is a logical hint.
Every row and column contains exactly half zeros and half ones. Once a line reaches its quota, every remaining cell is forced to the other value.
00_ and _00 force a 1 at the open end. A pattern such as 0_0 forces a 1 in the gap. The Logic Lens names both deductions rather than exposing an answer cell.
No two completed rows or columns can match. V0.230 enumerates every balanced, no-triple completion of a line and can prove when uniqueness removes the last alternative.
The bank spans 6×6, 8×8, 10×10, 12×12 and 14×14 at Easy, Medium and Hard. Every source and all eight geometric symmetries are independently rechecked before sealing.
Verified Hint, state verification, candidate marks, Check, Undo, Redo and Restart mark the run Assisted. Color mode and keyboard controls do not.
Date-stable Daily puzzles, Practice seeds, recent runs, bests and streaks remain browser-local. No account, ranking fiction, paid API or remote gameplay dependency is required.
Two matching neighbors force the open cell beside them to the opposite digit.
Matching digits with one gap force the gap to the opposite digit.
When a row or column reaches its quota, every remaining cell flips to the other value.
Rule-valid line completions that would duplicate a completed line are removed.
If every legal completion of a line agrees on a cell, that cell is forced.