5 × 5 is Hitori's starter size and the format of our daily puzzle. Every rule of the game shows up — duplicate elimination, the no-adjacent-shading rule, and keeping the white cells connected — but the deduction chains stay short enough to hold in your head.
Small boards are also where the classic patterns are easiest to spot: a triple like 3-3-3 in a row means both ends must be shaded, and a sandwich like 2-5-2 proves the middle cell stays white. Once those clicks, bigger grids are the same game with longer chains.
New to the rules? Start with the how-to-play guide, or jump straight into today's daily Hitori.