Ready to put the swordfish technique into action? This page is designed for you to practice and master swordfish patterns with real Sudoku puzzles.
Every board above is a position from a real puzzle where the Swordfish is the next step. Tap the candidates it removes (or select a cell and press the digit) and press Check. If you’re stuck, Show me gives the answer and Next puzzle loads another. Want to watch one first? Switch to Worked example.
Quick Reminder: What is a Swordfish?
A swordfish occurs when a candidate number appears in only three columns within three different rows (or vice versa). When you spot a swordfish, you can eliminate that candidate from all other cells in those columns (or rows).
Want a full step-by-step guide? Read the Swordfish technique article
How to Practice
- Scan the grid for a candidate that appears in only three columns within three rows (or three rows within three columns).
- Eliminate that candidate from all other cells in those columns (or rows).
- On the board, tap each of those candidates to remove it.
- Press Check. On your first try you see how many you found; on the second, the ones you missed get a dashed ring.
Start Practicing on Full Puzzles
Once you can find the Swordfish on most boards without pressing Show me, take it into a full game. Expert puzzles are where this technique starts to come up, and the step-by-step solver will name the technique each time you get stuck.