16×16 sudoku
Mega-grid rules — 16 symbols, 4×4 boxes — with a live classic board to keep your constraint muscles warm until the 16×16 engine ships.
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16×16 sudoku
A 16×16 sudoku (mega / hexadoku-style) fills a 16-by-16 grid so each row, column, and 4×4 box contains each symbol once. Symbols are often 1–16 or 0–9 plus A–F — same uniqueness idea, four times the glass.
Generating and hinting a fair 16×16 in-browser is a later phase. This page locks the rules in plain English and offers a live classic 9×9 so you can keep your constraint muscles warm.
When
When to use
You searched 16×16 / mega sudoku; you want size rules before a huge UI.
When not
When not to
Normal 9×9 fight → hard / expert. Samurai overlaps → samurai sudoku. Mini sizes → mini sudoku.
Defaults
Assumptions
16×16 is not “hard 9×9 with tiny font.” Different alphabet length and 4×4 boxes. Playable mega board = later phase.
Steps
How
- Learn the size: 16 symbols and 4×4 boxes.
- Practice scanning houses on the classic board above.
- Use Hint / Pencil habits that transfer to larger grids.
- Return for the mega engine in a later phase.
Worked notes
Examples
- Looking at a mega box → box is 4×4, not 3×3 — sixteen cells per house
- Letter F used as a symbol → behaves like any other symbol — no math meaning
Watch-outs
Gotchas
- Printable 16×16 PDFs are not this page.
- We do not ship a broken 16×16 that cannot hint fairly.
- Diagonals are optional elsewhere — not assumed on this URL.
Nearby pages
Compare
Samurai: samurai sudokuExpert classic: expert sudokuStrategy: sudoku strategyPlay: play sudoku
Controls
Quick controls
- Hint — a cell/digit, technique name, and short reason.
- Check — flags conflicts without revealing the full grid.
- Pencil — candidate notes for empty cells.
- New puzzle — same difficulty band, fresh seed.
- Daily — fixed local seed for the calendar day.
- Erase — clear the selected cell (not givens).
FAQ
Common questions
Playable 16×16 today?
Not yet. The live board is classic 9×9 practice; the mega engine is a later phase.
Numbers or letters?
Common sets are 1–16 or 0–9 plus A–F. Either way, each symbol appears once per house.
Harder than evil 9×9?
Different shape and longer sessions. Evil 9×9 stays on the evil sudoku page.
Account required?
No signup. Practice progress stays in this browser’s local storage.