วิธีเล่น Clone Sudoku

Clone Sudoku is a variant where two highlighted regions of the same shape appear on the grid. The two regions are 'clones' — they must contain exactly the same digit arrangement. Every cell in one region holds the same digit as the corresponding cell in the other region. Standard Sudoku rules apply.

The two clone regions are the same shape and size. Each cell in one region is paired with the corresponding positionally-equivalent cell in the other region. Placing a digit in any cell of one clone immediately fixes that digit in the matching cell of the other clone.

Yes. The puzzle constructor ensures that the clone constraint is always consistent with Sudoku rules — the two regions are positioned so that corresponding cells are in different rows, columns, and boxes, allowing the same digit to appear in both without violating uniqueness.

The clone constraint effectively halves the number of independent cells to solve — every deduction in one region automatically applies to the other. Easy Clone puzzles resolve noticeably faster than classic Sudoku. Hard and expert puzzles use the clones to create complex bi-directional constraint chains.

Treat the two clone regions as a single constraint. Whenever you eliminate a candidate from a cell in one region, immediately eliminate it from the corresponding cell in the other. Focus on the rows, columns, and boxes that interact with both regions simultaneously.

Easy puzzles take 6–15 minutes. Medium puzzles run 15–30 minutes. Hard puzzles average 30–60 minutes and expert puzzles can take 60–90 minutes. The bilateral nature of the clone constraint makes mid-game breakthroughs especially satisfying.