Entering puzzles

Choose Import and paste the puzzle as text, or pick Open a file to read it from a .txt, .sdk, .ss or .hkl file. The app works out the format by itself. It accepts:

• 81 characters in one line, with . or 0 for an empty cell. A trailing # comment is ignored.
• Nine lines of nine characters, with or without grid borders (|, -, +).
• A candidate grid (the digits that are still possible in each cell).
• Exports of SimpleSudoku.
• HoDoKu's library lines (:0000:x:...), and the puzzle field of the q2 taxonomy lines.

Anything with fewer or more than 81 cells is rejected with a message. The puzzle also has to have exactly one solution; if it has none or several, the app says so and does not load it.

Sharing a puzzle

Copy offers four formats: the 81-character line of the givens, the puzzle with candidates (a candidate/PM grid), a HoDoKu library line, and a formatted grid. Save writes the same four formats to a file, which the browser downloads. Paste the givens anywhere, or into Import on another device. A link of the form /play/?p=<81 characters> opens that puzzle directly. The technique guides use this for their Open in app buttons.

New puzzle → Daily puzzle (today) opens a date-seeded daily challenge (/play/?daily=1) where every player gets the same board for that UTC date. When you solve a puzzle, the completion dialog offers Share result to copy your time, hints used and a direct link.

Printing

Print prints the board with the givens only, without candidates or the side panel; Print solution prints the board and the solved grid after it. Export PNG saves the board as a .png image file.

Extended print builds a book of puzzles. Add up to five sections; for each, choose how many puzzles (0 to 30), the level, the mode (Playing, Learning or Practicing) and whether to print the candidates. A Learning section uses the techniques from the Training dialog. Then pick a layout: one, two or four puzzles per page, portrait or landscape. Print the rating writes the level and score under each puzzle. Booklet is offered for the landscape layouts only; it imposes the pages so that printing them double-sided and folding in the middle makes a booklet.