Binary Puzzle

Fill every blank with 0 or 1. Each row and column needs equal numbers of each. Never place three identical numbers consecutively, horizontally or vertically. Every completed row must differ from every other row, and every completed column from every other column. A row may match a column.

Select 0, 1 or Erase, then tap a square. Tap the same value again to clear it. The underlined numbers are fixed clues. Conflicting choices stay on the board until you change or undo them.

Keyboard: Tab to the board; arrows move, Home/End move across a row. Enter or Space uses your selected action. Press 0 or 1 to enter that number; Delete or Backspace clears a square. Ctrl/Cmd+Z undoes; Ctrl/Cmd+Shift+Z or Ctrl/Cmd+Y redoes.

This finite collection has 12 original boards each at 6 × 6 and 8 × 8. Size is not a difficulty rating. Next chooses another board at your size. Switching size or restarting asks before replacing unfinished choices.

Local saving resumes your current board in this browser, without accounts or sync. Undo and redo history lasts for this session.

Two identical neighbours force the opposite number beside them. Two matching numbers with one blank between force the opposite number in the gap. When half a line is filled with one number, the rest must be the other.

Hint checks your current numbers, including mistakes. It explains a quota, a triple or a value proved by bounded search. Apply hint enters the number separately. A contradiction means a choice must be changed or undone; a search limit means the search did not prove a move within its budget.

Hints and reveals mark the board as assisted. Reveal replaces the whole board after confirmation.

Rules reference: BinaryPuzzle.com rules. This site uses original code, artwork and boards; no puzzles were copied from that source.