😀 How to play 16x16 Sudoku
By Miguel Arechaga
16x16 Sudoku, also called Super Sudoku or Hexadecimal Sudoku, is the giant version of the classic sudoku. It keeps the same idea, but with a much bigger board and 16 symbols instead of 9. It's the perfect challenge once the 9x9 starts feeling too small. Here are the rules and tips to master it.
What is 16x16 Sudoku?
It's a sudoku with 16 rows by 16 columns (256 cells) divided into 4x4 boxes. Since 16 distinct symbols are needed, it uses the numbers 1 to 9 and the letters A to G. The goal and the logic are identical to regular sudoku, just at a bigger scale.
Rules and how to play step by step
- Each row must contain the 16 symbols (1-9 and A-G) without repeats.
- Each column must contain the 16 symbols without repeats.
- Each 4x4 box must contain the 16 symbols without repeats.
- You start with some clue cells and fill in the rest with logic. Every puzzle has a unique solution.
Tips to solve 16x16 Sudoku
- Go box by box: with 256 cells it's better to focus on one 4x4 box at a time, rather than scanning the whole board at once.
- Chase the frequent symbols: find a symbol that already appears many times and place it in the boxes that don't have it yet; row-and-column elimination is very powerful.
- Note the candidates: with 16 options per cell, jotting down the possibilities helps you stay on track.
- Apply the same advanced techniques as in the 9x9: naked pairs, hidden singles, and so on. They work the same way, just with more symbols.
How it differs from regular sudoku
Compared to classic 9x9 sudoku, the 16x16 doesn't change the rules: it multiplies the size. It requires more patience and organization, but the satisfaction of finishing it is huge. If you'd rather go the other way, try 6x6 Sudoku or other sudoku variants to change up the board's shape.
The sector method: how not to get lost in 256 cells
The classic 16x16 mistake is scanning the whole board like a big 9x9: your eyes drown and the sense of progress vanishes. The sector method works far better: mentally split the board into its 4 quadrants (2 bands x 2 stacks of 4x4 boxes) and work one quadrant until exhausted before jumping to the next. Inside each quadrant, apply the usual order: scan the frequent symbols, then singles, and notes only where needed.
Second pillar: prioritise the most frequent symbols. In a 16x16 with 100+ starting clues, some symbols already have 10-12 appearances and nearly complete themselves; each one finished is one fewer constraint to track. Run through the list from 1 to G when you start and note the three most frequent: they are your way in.
Letters or numbers: reading the hexadecimal board
The usual notation is 0-9 plus A-F (hence "hexadecimal sudoku"), though 1-16 versions exist too. Logically nothing changes, but a practical tip: when taking notes, treat the letters as visual symbols — don't "read" them. The brain groups A-B-C-D better as shapes than as quantities, and at this board size visual recognition speed matters more than arithmetic.
Frequently asked questions
How long does a 16x16 sudoku take?
Between 45 minutes and 2 hours depending on level and practice. It's a long-session format: best with breaks, and our online version saves your progress so you can continue later.
Is it harder than an expert 9x9?
It's longer, not necessarily deeper: the techniques required are usually those of a medium-hard 9x9, sustained for much more time. The challenge is stamina and organisation, not exotic patterns.
What should I play if 16x16 feels too long?
Expert 9x9 with 23 clues offers maximum depth in half-hour sessions, and killer sudoku adds arithmetic without growing the board.
