Variant Sudoku

Parity Lines Sudoku Explained in One Short Example

0:15 · Parity lines · Variant Sudoku

A four-cell parity line starts 3, 8, 2, which fails because 8 and 2 are both even. 3, 8, 7, 4 passes because it goes odd, even, odd, even.

Full lesson and practiceFind Parity Lines puzzles

Transcript

  1. 0:02Along the line, digits alternate between odd and even.
  2. 0:068 then 2 are both even.
  3. 0:09Odd, even, odd, even.

The rule

Along a parity line, digits alternate between odd and even. An odd digit always sits next to an even one on the line, and an even digit next to an odd one.

The line splits into two sets of cells, and every other cell shares a parity. Work out one cell and you know the parity of every cell on the line.

Worth memorizing

  1. Every other cell shares a parity.

    Mark one cell and the whole line follows.

  2. There are five odd digits and four even ones, so long lines in one box are tight.

Practice parity lines in the lesson

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