Chain Sudoku 6×6 – Hard

Chain Sudoku 6x6

Chain Sudoku 6x6 is a smaller variant of Chain Sudoku with 6 rows and 6 columns. Numbers 1 to 6 are used. The connected cells form chains, and each chain must contain the numbers 1 to 6 exactly once.

This variant is clearer than Chain Sudoku 9x9 but shows the same fundamental idea: rows, columns, and chains are the key areas. The chains replace the usual regions.

Basic Rules

• The playing field consists of 6 rows and 6 columns.
• Each row contains the numbers 1 to 6 exactly once.
• Each column contains the numbers 1 to 6 exactly once.
• Each drawn chain contains the numbers 1 to 6 exactly once.
• The chains are the additional regions of the puzzle.
• The given numbers must not be altered.

Solving Strategies

1. Look for Almost Complete Chains

In 6x6 puzzles, chains are quicker to oversee. If a chain already has five numbers, only one is missing.

The marked chain already contains the numbers 1, 2, 4, 5, and 6. The only missing number is 3. Therefore, the empty chain cell in row 1, column 4 must be a 3.

The conclusion is clear because the chain as a region must contain the numbers 1 to 6 exactly once.

2. Use Small Set of Symbols Consistently

Since only the numbers 1 to 6 are involved, candidate lists are short. It pays off to note the missing numbers in each open chain immediately.

After entering 3, no other 3 can be in the same row, column, or chain. This immediately rules out candidates at other positions.

3. Do Not Confuse Chains with Blocks

In Chain Sudoku 6x6, chains are the relevant regions. Do not automatically think of normal 2x3 blocks unless they are drawn as regions in the puzzle.

Typical Solving Sequence

1. Start by looking for rows, columns, or chains with many numbers.
2. Determine missing numbers in these areas.
3. Check each possible cell against row, column, and chain.
4. Use chain entries immediately to eliminate candidates in connected cells.
5. Ensure each chain contains the numbers 1 to 6 exactly once at the end.

Common Mistakes

• Confusing chains with regular blocks.
• Entering a number only because of the row without checking the chain.
• Mistracking the course of a chain.
• Relying on guessing too early, although the small 6x6 structure often allows for logical conclusions.

Tips for Beginners

• Start with chains that already include four or five numbers.
• Write down the missing numbers of a chain.
• Always check row, column, and chain together.
• Use the smaller size to keep candidates clean and complete.

Chain Sudoku 6x6 is great for practicing the logic of chain regions. The rules are simple, but the unfamiliar regions require careful observation.