New: Kerb Clash, clear the jammed car parkNew: Sudoku and Minesweeper, classic puzzles that play offlineInstall any game to your home screen

Binairo No Repeats: Don't Copy a Line

The no-repeats technique says: when a line has two squares left, one of each colour, and a finished line running the same way matches it everywhere else, fill the two squares the other way round from that line. Filling them its way would copy it, which the rules don’t allow.

Open Binairo full screen for more sizes, saved progress and best times.

This is the fourth of the Binairo techniques.

The rule

  1. Find a line with exactly two empty squares, which need one of each colour.
  2. Look for a finished line running the same way (rows with rows, columns with columns) that matches it in every filled square.
  3. Fill the two squares the opposite way to that line.
No repeats: two squares left, and a row to avoid copying Two rows of six. The first is complete: yellow, teal, teal, yellow, teal, yellow. The second matches it in its first four squares, with squares 5 and 6 left: one of each colour. Teal then yellow would copy the first row, so it's yellow then teal. 1 2 3 4 5 6 1 2
The bottom row matches the top one in its first four squares. Teal then yellow would copy it, so squares 5 and 6 are yellow then teal.

In a real puzzle

On the 10×10 every technique page follows, it’s needed once, at step 35. Row 4 has two squares left, in columns 3 and 5, and needs one of each. Row 7 is finished and matches row 4 everywhere else, with yellow in column 3 and teal in column 5. So row 4 gets teal in column 3 and yellow in column 5.

Step 35: no repeats Hard level 2 at step 35, with row 4 highlighted and the squares this step settles marked. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
Step 35: row 4’s last two squares go the opposite way to row 7’s.

How often you’ll need it

Never on Easy, but on 41 of the game’s 50 Medium levels and 38 of the 50 Hard ones, usually just once or twice per puzzle. That’s what makes it easy to forget, and the reason it’s worth checking before you fill the last two squares of any line.

Next steps

Questions

Does a row have to differ from the columns too?

No. A row may match a column; it only has to differ from the other rows. Columns are compared with columns.