Sudoku vs Hitori: Which Logic Puzzle Fits You

Sudoku fills empty cells under three overlapping rules

Classic Sudoku starts with a partly filled 9x9 grid. Your goal is to complete it so every row, column, and 3x3 box contains the nine symbols exactly once. You normally work with missing values and candidates: if a heart cannot appear in eight cells of a Shapedoku row, the ninth legal position is forced. Harder deductions compare candidate sets across several cells, boxes, or lines of sight. Shapedoku keeps this structure but replaces digits with nine glowing shapes, so the puzzle's logic becomes visibly independent of arithmetic. You are still deciding what belongs in each empty cell. Notes help because one cell may have several possible shapes until enough surrounding information removes the alternatives. Sudoku therefore rewards systematic scanning, candidate maintenance, and the ability to combine overlapping restrictions without losing track of which unit produced each elimination.

Hitori starts full and asks you what to remove

Hitori begins with a grid already filled with numbers. Instead of entering missing values, you shade cells so that no unshaded number appears more than once in any row or column. The shaded cells cannot share an edge, and all unshaded cells must remain connected as one continuous network. Those three rules create a different kind of deduction. If a cell is confirmed unshaded, every matching number in its row and column must be shaded. If a cell is shaded, its orthogonal neighbors must stay unshaded because two shaded cells may not touch by a side. Connectivity adds a global check: a shading choice is impossible if it would split the remaining white cells into separate areas. Hitori therefore asks you to classify existing cells rather than fill missing ones. The numbers identify duplicates, but the final pattern is a network of kept and removed cells.

Notice how duplicate patterns create different deductions

A useful Hitori pattern appears when two equal numbers sit next to each other in one row or column. They cannot both remain white because that would leave a duplicate, and they cannot both be shaded because shaded cells cannot share an edge. Exactly one of the pair must therefore be shaded. Any third copy of that same number in the same row or column must be shaded, because whichever adjacent copy remains white would conflict with it. This kind of reasoning has no direct Sudoku equivalent. Sudoku simply forbids duplicate final values inside its units and usually starts with empty space between clues. Hitori instead uses the tension between duplicate removal, non-touching shaded cells, and white-cell connectivity. Choose Sudoku when you enjoy candidate sets, box interactions, and techniques that grow from singles into chains. Choose Hitori when you enjoy shading logic and deductions where a local duplicate can affect the connectivity of the whole board. Shapedoku is a calm entry point to the Sudoku side, with Easy through Extreme difficulties, smart Notes, and Hints when a longer solve stalls.

• Choose Sudoku if you prefer filling empty cells with one symbol from a candidate set.
• Choose Hitori if you prefer deciding which existing numbered cells should be shaded.
• In Sudoku, rows, columns, and boxes must each contain every symbol once.
• In Hitori, unshaded numbers cannot repeat in a row or column, shaded cells cannot share an edge, and white cells stay connected.
• Use candidate Notes for difficult Sudoku and explicit white or black markings for difficult Hitori.
• Try both if you want to switch between placement logic and elimination by shading.