X-Cycles
Extreme
Used by Smart Hint
A single digit's strong and weak links are traced into a closed loop — a continuous loop yields eliminations at its weak links, a discontinuous one pins or clears its meeting cell outright.
- First colour in the chain
- Second colour in the chain
- Where the conclusion lands
- Candidate ruled out
How it works
- Digit 7 traces a closed loop: A1 ↔ F1 (row 1's only two 7s, strong), F1 ↔ F5 (column F's only two 7s, strong), F5 ↔ A5 (row 5's only two 7s, strong), A5 ↔ A1 (column A's only two 7s, strong) — a continuous loop since it alternates and closes evenly.
- Every weak link in a continuous loop gives an elimination — but here all four links happen to be strong, which itself forces the loop's two colors (teal/red) to alternate consistently around it.
- C5 sees both a teal cell (A5) and a red cell (F5) in the loop — since one color must be true, 7 is eliminated from C5. (A discontinuous loop, where two strong links meet at one uncolored node instead of closing evenly, would place or clear that single node directly rather than eliminate elsewhere.)