Kakurasu (PuzzleMadness)

About 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 plus a Mixed page, and the same day's Kakurasu puzzle is shared by everyone who opens it.

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.

How to play Kakurasu (PuzzleMadness)

1. Open today's Kakurasu page on PuzzleMadness and choose a difficulty from the menu above the grid.
2. Click a cell to shade it; each shaded cell counts as its column number in its row and its row number in its column.
3. Mark cells that must stay empty with a dot so you can keep track of them.
4. Keep going until every row and column adds up to the total printed beside it.
5. The site tells you when the grid is complete and adds your score; registered players appear on the leaderboards.

Screenshots

Tips

• Start with the smallest totals: a row total of 3 can only be 1 + 2 or 3, so every cell worth 4 or more in that row is empty.
• Large totals work the other way: list the ways to make them and fill the cells that appear in every option.
• Once part of a line is filled, subtract it from the total and solve the rest as a smaller sum.
• Missed a day? Earlier puzzles are in the archive, and finishing one still counts toward this month's leaderboard.

Questions