
A Singles Chain has six candidates: four red candidates
'1' in cells C3, B8, G7, and I1, and two green candidates in G3 and I8. If the red candidates
'1' in C3 and B8 are ON, all other candidates '1' in rows B and C should be eliminated, including both candidates
'1' (marked orange) in the middle 3x3 square in the first row. This would make the sudoku invalid. To avoid this scenario, all Singles Chain red candidates should be OFF. All green candidates should be assigned to the cells as valid sudoku solutions.
The X-Chain Details:
- B8(1) => I8(1) - If 1 in cell B8 is ON, then 1 in cell I8 is OFF.
- I8(1) => I1(1) - If 1 in cell I8 is OFF, then 1 in cell I1 is ON.
- I1(1) => G3(1) - If 1 in cell I1 is ON, then 1 in cell G3 is OFF.
- G3(1) => C3(1) - If 1 in cell G3 is OFF, then 1 in cell C3 is ON.
- I8(1) => G7(1) - If 1 in cell I8 is OFF, then 1 in cell G7 is ON.