Solo Puzzle Online

Solo is one of the classic one-player logic games in Simon Tatham's Portable Puzzle Collection. Fill in the grid so that each row, column and square block contains one of every digit.

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Preparing the game board and controls.

What This Game Is

Solo is a self-contained logic puzzle built around one clear objective. Each new board gives you a fresh problem to solve, so it works well for quick sessions and repeated play.

Fill in the grid so that each row, column and square block contains one of every digit.

How to Play

To play Solo, simply click the mouse in any empty square and then type a digit or letter on the keyboard to fill that square. If you make a mistake, click the mouse in the incorrect square and press Space to clear it again (or use the Undo feature). If you right -click in a square and then type a number, that number will be entered in the square as a ‘pencil mark’. You can have pencil marks for multiple numbers in the same square. Squares containing filled-in numbers cannot also contain pencil marks.

Most puzzles in this collection reward deduction more than speed. Focus on the most limited choices first, use the clues to narrow the board, and avoid guesses unless the puzzle mode clearly expects them.

Beginner Tips

  • Start with the area that has the strongest clue or the fewest legal options.
  • Use marks, notes, or temporary indicators if the puzzle supports them.
  • Try to preserve flexibility instead of committing too early when multiple moves look possible.
  • If the board gets messy, restart a fresh puzzle and apply what you learned from the first run.

Official Reference

If you want the full original rule explanation, examples, and advanced options, the official manual is the best reference.

Read the official manual

Frequently Asked Questions