Daily edge-clue logic grid
EdgeSum
Fill the 5x5 grid so every row and column sum matches the edge clues. One unique solution every day, provable by pure logic — no guessing.
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Frequently asked questions
How do the sum clues work?
Each row and column has a clue on its edge — the target sum of all filled cells in that row or column. A filled cell contributes a fixed numeric value based on its position, shown faintly inside the cell. Your job is to choose which cells to fill so every row and column sum matches its clue exactly.
Is there always exactly one solution?
Yes. The daily generator runs a solver over every candidate board and only ships boards with a unique solution. You never need to guess — every daily board is deducible by pure logical chains.
What does marking a cell do?
Marking (the X state) has no effect on the sums — it’s a memory aid to track cells you’ve ruled out by deduction. It works like the X marks in Nonogram or Sudoku pencil-marks.
Is the daily board the same for everyone?
Yes. The board is seeded from the current UTC date, so every player worldwide faces the identical puzzle — your tap-count and hint-count are directly comparable with friends.
About EdgeSum
EdgeSum is a daily edge-clue logic puzzle inspired by the Nonogram, Kakuro, and Sudoku traditions. Every day, a fresh 5x5 grid ships with row and column sum clues along each edge. Your job is to deduce — by pure forced-move logic, with no guessing — which cells to fill so every row and column sum matches its clue exactly. Each daily board is machine-verified to have a unique solution.
How to play
Tap a cell to cycle its state: empty -> filled -> marked -> empty. Filled cells contribute a value (shown faintly inside each cell) to their row and column sums. Your goal is to match every edge clue. Marked cells are pencil-marks — they don’t contribute to sums, but they help you track what you’ve ruled out. The clue panel beside each row and column turns green when its sum matches.
Why a daily constraint-logic puzzle?
Constraint-propagation puzzles — the family that includes Sudoku, Nonogram, Kakuro, and Hashi — exercise a distinct cognitive skill: one-shot deductive inference, where you read all the clues simultaneously and derive the unique solution by chaining forced moves. This is different from trial-and-error deduction (Mastermind, Wordle), different from reflex games, and different from path search. EdgeSum compresses this deep logical tradition into a 5x5 daily ritual — short enough to solve on a coffee break, deep enough to stretch the deductive muscle.