Rossini Sudoku (PuzzleMadness)

About Rossini Sudoku (PuzzleMadness)

The standard rules apply: 1 to 9 once in every row, column and 3x3 box. Around the outside of the grid, arrows sit at the ends of some rows and columns and refer to the first three cells from that edge. An arrow pointing in towards the grid means those three digits increase as you move inwards, lowest at the edge. An arrow pointing away from the grid means they decrease as you move inwards, highest at the edge. Where there is no arrow, the three digits must not be in order either way.

The empty edges are as useful as the arrows, since three digits that are neither rising nor falling must have the middle one as the highest or the lowest. Because each arrow covers exactly the three cells of one box along that line, the clues also work well with the box rule.

The grid works like every sudoku on PuzzleMadness: number buttons above and below it, an eraser, and a pencil mode for candidate digits. On a keyboard, the number keys enter digits, the arrow keys move between cells, Ctrl, Shift or Alt with a number adds a pencil mark, and Delete or Backspace clears a cell.

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. Rossini Sudoku comes in Easy, Medium, Hard and Tough versions plus a Mixed page, and the same day's Rossini Sudoku 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 Rossini Sudoku 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 Rossini Sudoku (PuzzleMadness)

1. Open today's Rossini Sudoku page on PuzzleMadness and choose a difficulty from the menu above the grid.
2. Click a cell and enter a digit with the number buttons above and below the grid or with the keyboard; the eraser button clears a cell.
3. Fill every row, column and 3x3 box with the digits 1 to 9, each once.
4. Where an arrow points into the grid, make the first three digits from that edge increase; where it points away, make them decrease.
5. Where an edge has no arrow, make sure the first three digits from it are neither increasing nor decreasing.
6. Turn on pencil mode (the pencil button, or Ctrl, Shift or Alt with a number key) to jot candidate digits in a cell.
7. The site tells you when the grid is complete and adds your score; registered players appear on the leaderboards.

Tips

• In a rising trio the edge cell can be at most 7 and the third cell at least 3.
• No arrow means the middle cell of the three is either the largest or the smallest of them.
• Arrows on two edges of the same box give two orderings through shared corner cells, which often fixes the corner.
• Missed a day? Earlier puzzles are in the archive, and finishing one still counts toward this month's leaderboard.

Questions