About Hidato Puzzle
Hidato Puzzle is a small site built around one puzzle done properly. Every board here is free to play in your browser and free to print — no account, no sign-up, and no “unlock the solution” nonsense.
What Hidato is
Hidato — also written Hidoku, and known informally as a number snake — is a logic puzzle invented by the mathematician Gyora Benedek. You fill every empty cell so the numbers form one unbroken chain from 1 to the highest number, with each number touching the next. On the honeycomb boards used here, every cell touches six neighbours, which gives the chain more room to turn than a square grid does.
There is no arithmetic and nothing to guess. Every step follows from the board in front of you. If you have never solved one, the walkthrough takes a real 19-cell board from first clue to finished grid.
The library
There are 203 puzzles at the moment, from 19-cell boards you can finish over a coffee to 81-cell honeycombs that will hold you up for a while.
How the puzzles are made
Every board is laid out by hand rather than churned out by a generator: the shape is drawn first, then the path from 1 to the last number, then the clues are chosen one at a time. Machine-generated puzzles tend to feel samey, and the clue placement is what makes a Hidato pleasant or tedious to solve.
Before a puzzle is published, its solution is checked automatically: every number from 1 to the last must appear exactly once, and each must sit next to the one after it. Each puzzle page also runs a short search over the board to find openings where only a single route is possible — that is where the “where to start” hints come from, so they are worked out from the board itself rather than written by hand.
Printing
Every puzzle has a two-page PDF: the board on page one, the solution on page two. They are drawn as vector graphics, so they stay sharp at any size and print cleanly in black and white. The sheets are A4, laid out so nothing is cut off on US Letter either.
Teachers, parents and puzzle groups are welcome to print and copy them freely for personal or classroom use. Browse the printable puzzles.
On your phone
The same puzzles are available as a mobile app for iPhone and iPad and for Android. On the web, your progress on a puzzle is kept in your own browser, so you can close the tab and pick the board up where you left it.
Get in touch
Found a board that does not work, a hint that reads wrong, or a puzzle you loved? Email voxlab.dev@gmail.com. Corrections are genuinely welcome — a broken puzzle is worth knowing about.