Extreme Killer Sudoku 3, puzzle 114: step-by-step solution
Step through the whole solution, or skip to the hard parts. Blue digits are placed by the walkthrough; red strike-through marks a candidate being ruled out.
Blue digits are placed by the walkthrough. Red strike-through marks a candidate being ruled out. Cells are named by row and column: R3C5 is row 3, column 5. Arrow keys step too.
The key technique: Forcing Chains
Try each candidate of one cell in turn. Every choice leads to the same result, so that result must be true.
Other advanced and expert techniques in this solve: Advanced Innies (3+ sectors) (×2), Coloring/Multi-coloring, Multi-Sector Locking, Skyscraper.
Every move above the basics is listed on the killer sudoku techniques page, each with a one-sentence explanation and worked examples from the books.
The hard steps, in text (6)
- Step 16 · Advanced Innies (3+ sectors) advanced
Places 5 in R7C3 and rules out 5 from R1C3, R2C3, R3C3, R5C3 and 7 more; 4 from R5C2, R5C9; 6 from R5C2, R5C4, R5C5. - Step 27 · Skyscraper advanced
Rules out 5 from R1C4. - Step 28 · Advanced Innies (3+ sectors) advanced
Rules out 2 from R2C6, R3C6; 4 from R2C6, R3C6. - Step 33 · Forcing Chains expert
Rules out 1 from R1C8. - Step 36 · Multi-Sector Locking advanced
Rules out 2 from R3C3, R4C3. - Step 41 · Coloring/Multi-coloring expert
Rules out 1 from R1C4, R3C2.
The book
Volume three: 150 new killers, none repeated from books 1 or 2. No starting digits, just cages and their totals, ramping from hard to brutal.
150 new puzzles. Expert and beyond. Puzzles by M. J. Bailey. Paperback, 5 × 8 in, 196 pages, £9.99 / $11.99. Every solution in the book carries a QR code to its own walkthrough, so you can check one step without seeing the whole answer.
Try a free sample puzzle (PDF) · prints on A4 or US Letter
More step-by-step solutions: Extreme Sudoku 1 · Extreme Killer Sudoku 1 · Extreme Sudoku 2 · Extreme Killer Sudoku 2 · Extreme Sudoku 3.