Sahi Trace

Sahi Trace is a free daily path puzzle. You are given a grid with some numbered cells, and you draw one continuous line that passes through every cell exactly once while visiting the numbers in order. There are five grids each day, starting at an easy 4×4 and building up to a full 6×6, and the set is the same for every player until midnight IST.

The rules are short. The line starts at number 1 and ends at the highest number. It moves between cells that share an edge, never diagonally. It must enter every cell on the board exactly once, with no cell left out and none used twice. The numbered cells must be reached in ascending order. A grid is complete when one unbroken path satisfies all four conditions.

Drag across the grid to draw, or tap cells one after another. Dragging back over your own path erases it, so you can retreat a few steps without starting again, and the reset control clears the grid entirely.

What makes these puzzles interesting is how heavily a path through every cell is constrained: a corner can only be entered and left one way, and a cell with a single free neighbour has to be an endpoint. Spotting those forced moves first, then filling the open middle, turns a long search into a short one. This is a Hamiltonian path problem, the same shape of question that appears in route planning and circuit layout.