Techniques · sudoku and killer sudoku
Finned Fish
An X-Wing or Swordfish with one extra candidate (the fin). Cells that are in the fish pattern and also see the fin lose the digit.
In the walkthroughs, every Finned Fish step shades the cells of the pattern and names the cell and digit it proves, so you can see the move on the grid rather than read about it. Press “Skip to next hard step” to jump straight to it.
Worked examples
Puzzles from the books where Finned Fish is used, those where it is the key technique first. Each link opens the full step-by-step solution.
Extreme Sudoku 1 (127 of 150 puzzles)
- Puzzle 40 · Expert 7 · key technique
- Puzzle 141 · Expert 7 · key technique
- Puzzle 148 · Expert 6 · key technique
- Puzzle 1 · Expert 5
- Puzzle 2 · Expert 5
- Puzzle 3 · Expert 5
- Puzzle 4 · Expert 5
- Puzzle 5 · Expert 5
Extreme Killer Sudoku 1 (35 of 150 puzzles)
- Puzzle 4 · Expert 2 · key technique
- Puzzle 10 · Expert 4 · key technique
- Puzzle 11 · Expert 3 · key technique
- Puzzle 16 · Expert 3 · key technique
- Puzzle 30 · Expert 2 · key technique
- Puzzle 76 · Expert 2 · key technique
- Puzzle 81 · Expert 3 · key technique
- Puzzle 89 · Expert 3 · key technique
Extreme Sudoku 2 (132 of 150 puzzles)
- Puzzle 1 · Expert 5 · key technique
- Puzzle 36 · Expert 7 · key technique
- Puzzle 75 · Expert 7 · key technique
- Puzzle 113 · Expert 7 · key technique
- Puzzle 144 · Expert 6 · key technique
- Puzzle 3 · Expert 5
- Puzzle 4 · Expert 5
- Puzzle 5 · Expert 5
Extreme Killer Sudoku 2 (29 of 150 puzzles)
- Puzzle 6 · Expert 3 · key technique
- Puzzle 9 · Expert 3 · key technique
- Puzzle 14 · Expert 3 · key technique
- Puzzle 29 · Expert 2 · key technique
- Puzzle 31 · Expert 2 · key technique
- Puzzle 36 · Expert 3 · key technique
- Puzzle 37 · Expert 2 · key technique
- Puzzle 53 · Expert 2 · key technique
Extreme Sudoku 3 (135 of 150 puzzles)
- Puzzle 148 · Expert 7 · key technique
- Puzzle 1 · Expert 5
- Puzzle 2 · Expert 5
- Puzzle 3 · Expert 5
- Puzzle 4 · Expert 5
- Puzzle 5 · Expert 5
- Puzzle 6 · Expert 5
- Puzzle 7 · Expert 5
Extreme Killer Sudoku 3 (44 of 150 puzzles)
- Puzzle 3 · Expert 2 · key technique
- Puzzle 51 · Expert 2 · key technique
- Puzzle 57 · Expert 2 · key technique
- Puzzle 62 · Expert 2 · key technique
- Puzzle 64 · Expert 2 · key technique
- Puzzle 66 · Expert 2 · key technique
- Puzzle 69 · Expert 2 · key technique
- Puzzle 74 · Expert 2 · key technique
Where it sits
See the whole ladder on hard sudoku techniques and hard killer sudoku techniques, or look a puzzle up by number under solutions.
