Hitori – Hard

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Hitori, originating from the Japanese phrase "Hitori ni shite kure" which translates to "Leave me alone," is a logic puzzle that engages solvers in a grid filled with numbers. The puzzle begins with each square of the grid containing a number. The objective is to strategically color some cells to ensure no duplicate numbers appear in any row or column, bearing a resemblance to the solved state of a Sudoku puzzle.

Basic Rules

1. No Duplicates: Color the cells in such a way that no duplicate numbers are present in any row or column.
2. Orthogonal Connections: Pay attention to the connections between the cells, both colored and uncolored.

Additional Rules

1. Black Cell Placement: Colored (black) cells must not be orthogonally connected.
2. White Cell Placement: All uncolored cells must be orthogonally connected, forming a single group.

Basic Solving Tips

• Spot Obvious Duplicates: Begin by identifying and coloring cells that are obvious duplicates in rows or columns.
• Ensure Connectivity: While coloring, ensure that the uncolored cells remain connected orthogonally.
• Avoid Isolation: Be cautious not to isolate any uncolored cell, ensuring they are part of the larger uncolored group.
• Check Rows and Columns: Regularly check rows and columns to ensure no new duplicates are created as you color cells.