Kakurasu (PuzzleMadness)

Kakurasu is played on a square grid with the numbers 1, 2, 3 and so on along the top and left edges and a target total at the end of every row and column. Filling a cell adds its column number to that row's total and its row number to that column's total. The puzzle is solved when every row and column adds up exactly, with the remaining cells left empty. You can mark cells you know are empty with a dot.

The logic is a mix of sum-splitting and elimination: a small total rules out the larger cells in its line at once, a total near the maximum forces the larger cells in, and each filled or dotted cell narrows the options in the crossing line. The site's rules page walks through a 7x7 example step by step.

PuzzleMadness is a free puzzle website run by Dewi, a software developer who started out making games for the PlayStation 2, Nintendo Wii and DS and now builds the site as a hobby. It carries dozens of puzzle types, from classic sudoku to newer logic grids, and each one gets its own dated puzzle every day at each difficulty. Kakurasu comes in Small, Medium and Large versions, and the Mixed page has a fourth grid of its own rather than a copy of one of the others. On 28 October 2026 the sizes were 6x6, 7x7 and 10x10, with a different 7x7 grid on the Mixed page. Each day's grids are shared by everyone who opens them.

The site checks your grid as you go and tells you when it is finished; it does not publish solutions. Each completed puzzle earns a score, and scores feed a monthly and an all-time Kakurasu leaderboard, where only your best attempt at a puzzle counts. Older days stay in the archive, so a missed puzzle can still be played later and still counts toward the current month. Playing needs no account; a free registration gives you a username on the leaderboards and a cloud save. The pages carry adverts.