About WindowToo

A 9x9 puzzle, and the color twin of Window: the same rules, colors in place of digits. The two never play the same board on the same day.

WindowToo is a free daily color windoku from Mind Loft. Each day gives you a 9×9 grid with one rule added to the usual three: four shaded windows, the 3×3 blocks that sit between the boxes, also hold all nine colors exactly once. Rows, columns, and 3×3 boxes still do too, and those four extra houses do enough of the work that the board can print far fewer colors than an ordinary sudoku needs.

There is no arithmetic: the windows are tinted and framed, and selecting a square in one lights the whole window as a peer, the same way its row, column and box light up. Each window overlaps four boxes, which is where most of the fun is. Every board has a single solution you can always reach by logic, with no guessing, and on every board the windows are load-bearing rather than decorative: read as an ordinary sudoku, the same clues would fit more than one grid. Wrong entries are never flagged, so spotting your own slips is part of the puzzle, and a clean solve scores a perfect 10 with the daily leaderboard decided on the clock.

A new board drops every day at midnight Eastern; weekdays print fewer colors as the week goes on, from 22 on Monday down to 14 on Saturday, and the Sunday Edition prints thirteen. No app, no signup, play free in your browser. Want the rest of the family? Try Suds, the classic 9×9, Diag, the diagonal sudoku, Cages, the killer sudoku, and Polka, the kropki with no colors at all.