AI Super Solver
Nudges, walkthroughs & “Why not?”
Let the AI Coach guide you in four stages—from where to look to the final move—or tap any cell candidate to watch the chain of forced moves that proves a contradiction.
The HoDoKu sudoku solver, now with AI Super Solver & Coach
Every sudoku step,
explained.
A free sudoku solver and trainer: the hint engine, analyzer and technique library from HoDoKu, rebuilt in TypeScript with an interactive AI Coach. No Java and no install. Get progressive nudges, step through every deduction on the board, or ask why any candidate fails.
New · AI Super Solver & Coach
Ask “Why not?” on any cell—and watch the proof unfold.
Stuck between two candidates? Select any cell and ask the AI Coach “Why not 4?” It tests your hypothesis, traces the forced singles that ripple across the board, and highlights the exact contradiction.
1. Assume → 2. Forced moves → 3. Contradiction
“Suppose we place 4 in r1c9. That forces 5 into r1c8 and 6 into r2c9… leaving Row 8 with no valid cell where digit 3 can go. Therefore, r1c9 cannot be 4.”
Prefer not to spoil a hint? Click Coach me for progressive four-stage Socratic nudges—starting with where to look before revealing the pattern or the move.
Hints
Vague, concrete or the full step
You choose how much a sudoku hint gives away. Start with a Socratic nudge, name the technique, or highlight every candidate involved.
Analyzer
See the whole solution path
Get the techniques the solver would use and the hardest one required, plus a difficulty rating for any sudoku puzzle you paste in.
Library
From singles to last resort
32 technique guides, written new. Every example is a board you can step through and open in the app.
New to sudoku or looking for HoDoKu?
Read how to solve sudoku step by step, see what the difficulty levels mean, look up a word in the glossary, or learn how to run HoDoKu online on Mac, Windows & mobile (no Java).
This sudoku solver finds the same steps as HoDoKu 2.2.0 (we compare them step by step), so a hint is always a real technique, never a guess. It runs entirely in your browser and works offline once installed.