Suguru

Easy suguru uses a 6×6 grid with cages of 3 to 4 cells. About half the cells come pre-filled, so you can focus on learning the two core rules: each cage of N cells holds digits 1 through N, and no two touching cells (including diagonals) share a digit.

Start by looking for cages with only one empty cell. The missing digit is forced. Then scan for cells where adjacency elimination leaves a single candidate. These naked singles chain into each other: filling one cell often forces the next.

Once easy puzzles take you under 3 minutes, try medium.