How to play Gridlock

Fill every cell in the 5×5 grid with a digit from 1 to 5. The rules are simple:

• No digit repeats in any row
• No digit repeats in any column
• Each colored zone (outlined by thick borders) must sum to the target number shown in its top-left corner

Tap a cell to select it, then tap a number (1-5) to fill it in. Red numbers indicate conflicts (duplicate in same row or column). The timer starts on your first move.

Gridlock vs Sudoku

Gridlock is like a simplified, faster Sudoku. A 5×5 grid with digits 1-5 means fewer possibilities to track, but the zone sum constraints add a unique twist. Typical solve times: Easy 1-3 minutes, Medium 3-5 minutes, Hard 5-10 minutes.

Solving strategy

• Start with given cells: Mark which digits are already used in each row/column
• Small zones first: A 2-cell zone with a sum of 3 can only be 1+2
• Use elimination: If a row already has 1,3,4,5 — the empty cell must be 2
• Zone constraints: If a 3-cell zone sums to 12, and one cell is 5, the other two must sum to 7 (3+4 or 2+5)