Hitori Island is a logic puzzle played on a grid that has been divided into individual cells. Each cell contains a number. The aim of the puzzle is to eliminate duplicate numbers so that no number appears more than once in any row or column.

When all duplicates have been eliminated (turned into blue water cells) the remaining gold cells (sand) create an island. The blue cells cannot isolate any part of the island - it must remain a single shape. You must be able to reach every part of the island without swimming.

Game Rules

  • To eliminate a duplicate number, use the mouse to click on any cell. That cell will turn blue.
  • Highlighting the cells which must be gold will make the puzzle easier to solve. Click on the cell and and hold the mouse down for half a second. A circle will appear around that number.
  • Blue cells cannot be horizontally or vertically adjacent, although they can be diagonally adjacent.
  • The gold cells must not be isolated from the rest of the grid by blue cells either vertically, horizontally or diagonally.
  • Cross-hatching will appear to indicate that you have correctly completed a row or column.

Techniques to Solve Hitori Island

  • If a number has been circled to show that it must be gold, any cells containing the same number in that row or column must be blue.
  • If turning a cell blue would isolate a gold area from the rest of the island, then that cell must be gold.
  • Where there are three identical, adjacent numbers, the centre number must be gold. If either of the end numbers were gold this would result in two adjacent blue cells which is not permitted.
  • Where a number has two identical numbers on either side of itself, it must be gold. This is because one of the two identical numbers must be blue, and it cannot be adjacent to another blue cell.
  • Where there are four identical numbers in a 2X2 square on the grid, two of them must be blue along a diagonal. There are only two possible combinations, and the correct option is sometimes revealed by determining if one combination will isolate gold cells from the island.
  • Where four identical numbers form a square in a corner of the grid, the corner square and the one diagonally opposite must be blue. The alternative would isolate the gold corner square from the island.
  • Where duplicate numbers appear, it is not always the case that one cell must remain gold; it is possible that they should all be blue.

Game Options

SAVE: Click to save your Hitori Island puzzle

  • YouPlay Premium Members receive 10 save slots
  • YouPlay Members receive 3 save slots

PAUSE: Click to halt the timer if you wish to pause during game play

EXIT: Click to return to the Game Selection page

UNDO: Undo your moves one click at a time

CLEAR GRID: Undo all moves and start the Hitori Island puzzle again

Game Features

TOKEN COUNTER: Displays how many tokens you have won during the game

TIMER: The timer starts as soon as you open the Hitori Island puzzle

YouPlay BOOST: Boost your score – multiply your points by working faster and smarter

HINTS: Click to add an extra number to help you solve the Hitori Island puzzle

  • YouPlay Premium Members receive 3 hints
  • Youplay Members receive 3 hints

Note: As you begin some 'Easy' level Hitori Island puzzles, you may notice that a row or column has already been cross-hatched. This is because no blue squares are required in that row or column. Simply continue solving the rest of the puzzle.