How Number Snake Puzzles Work

Summary:
Number Snake is a logic puzzle where you fill the missing numbers so that 1 to N form one continuous chain through every cell. This tutorial explains the goal, the Orthogonal (Numbrix) and Diagonal (Hidato) variations, and how to start solving.

Overview

A Number Snake puzzle is a grid with some numbers already printed as clues. You fill in the rest so the numbers run in an unbroken sequence — each number sitting next to the one before it — until the whole board is full. It is easy to learn and gets harder as the grid grows and clues thin out.

Screenshot to capture (see shot-list.md): play-01-puzzle-solution.png, a Number Snake puzzle and its solved grid side by side.

The Goal

Fill every empty cell so that:

Every number from 1 to N appears exactly once (N is the number of cells — 49 on a 7×7 grid).
Consecutive numbers are always in neighbouring cells.
The finished numbers trace a single continuous path through the whole grid.

The printed clues are fixed; your solution must keep them in place.

Orthogonal Mode (Numbrix)

In Orthogonal mode, consecutive numbers may only touch up, down, left, or right — never diagonally. This is the classic Numbrix rule. Fewer neighbours per cell means tighter constraints and more deduction.

Diagonal Mode (Hidato)

In Diagonal mode, consecutive numbers may touch in any of the eight surrounding cells, including the four diagonals. This is the Hidato rule. More possible neighbours gives you more freedom, but harder puzzles still come down to careful logic.

How to Start Solving

Bridge close clues. Two clues a step or two apart — like 12 and 14, or 37 and 39 — usually leave only one or two cells where the number between them can go.
Work from the ends. The lowest and highest clues anchor the start and finish of the chain, so the path cannot continue past them.
Find forced moves. When the next number has only one valid neighbouring cell, that placement is forced. Forced moves are your most reliable progress.
Follow the emerging chains. Extend partial runs of the path rather than solving numbers in isolation — connected segments reveal further placements.
Avoid guessing. Before writing a number, check it is the only option and that it still leaves room for every remaining number.

A well-formed Number Snake puzzle is solvable by logic alone, so you should never need trial and error.

Outcome

You now understand the goal, the difference between Orthogonal (Numbrix) and Diagonal (Hidato) modes, and the first solving moves. Want to make your own? See How to Create Number Snake Puzzles in Puzzle Maker Pro.