Variant Sudoku

Entropic Lines Sudoku Explained in One Short Example

0:18 · Entropic lines · Variant Sudoku

A four-cell line starts 1, 8, 4, which is one low, one high and one middle digit. A 7 in the last cell fails because 8, 4, 7 has two highs, and a 2 works.

Full lesson and practiceFind Entropic Lines puzzles

Transcript

  1. 0:02Any three cells in a row on the line hold one low (1–3), one middle (4–6) and one high (7–9) digit.
  2. 0:061 is low, 8 is high, 4 is middle.
  3. 0:098, 4, 7 has two highs.
  4. 0:12So the next digit must be low again: 2 works.

The rule

Entropic lines split the digits into three groups: low (1 to 3), middle (4 to 6) and high (7 to 9). Any three cells in a row along the line must hold one digit from each group.

The rule turns the line into a repeating pattern. Once you know the groups of two neighboring cells, you know the group of every cell on the line.

Worth memorizing

  1. The pattern repeats every three cells.

    Cells 1, 4 and 7 on the line share a group.

  2. Once you know two cells’ groups, the third is forced.

Practice entropic lines in the lesson

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