Sudoku 16×16
Hexadecimal sudoku for marathon solvers.
What is sudoku 16×16?
Sudoku 16×16 uses a 16-row by 16-column grid divided into 4×4 boxes. We use the hexadecimal characters 0 through F so digits stay single-character. The puzzle's combinatorial space is enormous. even an easy 16×16 takes 30+ minutes.
Rules
- Each row contains every hexadecimal digit (0–9, A–F) exactly once.
- Each column contains every hexadecimal digit exactly once.
- Each 4×4 box contains every hexadecimal digit exactly once.
Tips
- Pencil marks aren't optional. every empty cell has up to 16 candidates.
- Hidden singles are still the most efficient first scan, but they're rarer in 16×16.
- Take breaks. 16×16 solves often run over an hour.
Related variants
- Sudoku 12×12, Twelve-digit sudoku for serious solvers.
- Samurai Sudoku, Five 9×9 sudokus joined at the corners. Solve them as one giant puzzle.
- Killer Sudoku, Sudoku meets killer-style arithmetic: every dotted region sums to its total.
- Classic sudoku for comparison
Sudoku 16×16 FAQ
Why hex digits in 16×16 sudoku?
Because each cell holds a value 0–15, and hex (0–9, A–F) keeps it to one character. Some publications use the numbers 1–16 instead, but that doubles cell width.
How long does a 16×16 take?
Easy ones are 30–45 minutes; hard takes several hours. Most solvers do them across multiple sessions.
Are 16×16 puzzles unique?
Yes, all Sudokly 16×16 puzzles are verified unique.
Do classic techniques work on 16×16?
Yes. naked singles, hidden singles, pairs, triples, X-wing all generalise. The candidate space is just much larger.
Is there a 16×16 daily puzzle?
Not yet. Our daily rotation is 9×9 only at launch. 16×16 is a planned addition once the engine is stable.