Arrow

About Arrow

Arrow is one of the sudoku variants on Mind Loft, a free puzzle site played in the browser with no app and no account needed. The grid follows the usual sudoku rules: every row, column and 3x3 box holds the digits 1 to 9 once each. On top of that, arrows are drawn across the grid. Each arrow starts in a circle and runs through a short line of squares, and the digit in the circle is the sum of the digits on its line.

A new board arrives every day at midnight Eastern time and is the same for everyone. The week has a shape: Monday's board prints 28 digits and each day prints fewer, down to 13 on Saturday, while the Sunday Edition gives just eight printed digits under twelve arrows, so most of the work is done by the sums.

The deductions are mostly about combinations. A circle of 3 on a two-square arrow can only hold 1 and 2, and a big circle on a long arrow forces small digits along it. A digit may repeat along one arrow only where the two squares share no row, column or box. Mind Loft says every board has a single solution reached by logic alone.

Wrong entries are not flagged while you play, so checking your own work is part of the puzzle. A clean solve scores a perfect 10, and the daily leaderboard is ranked by time. There are notes for pencil marks, a hint button, and an archive of past boards. Arrow suits sudoku players who know the classic grid and want arithmetic in the logic; Mind Loft's Cages (killer), Sando (sandwich) and Mercury (thermo) are its sibling variants.

How to play Arrow

1. Open mindloftdaily.com/arrow and press Start to see the day's 9x9 board.
2. Tap a square and then a number, or pick a number and then tap the squares to fill.
3. Place 1 to 9 once in every row, column and 3x3 box.
4. Make each circled digit equal the sum of the digits along its arrow.
5. Use Notes to pencil in candidates and Hint if you are stuck, then fill the last square to finish and see your time.

Screenshots

Tips

• Start with small circles on short arrows: a 3 on two squares can only be 1 and 2, and a 4 only 1 and 3.
• A circle can never be smaller than the number of squares on its arrow plus what repeats allow, so long arrows push their circles toward 7, 8 or 9.
• Because wrong digits are not flagged, check each finished row and column against the arrow sums before your last entries.
• Expect fewer printed digits as the week goes on and lean on the arrows for the Saturday and Sunday boards.

Questions