Consider this puzzle:

When you draw a line cutting off the first three columns, you have two innies R79C3 and two outies R13C4.

Because the number of innies equals the number of outies, they must share the same candidates. Other candidates which are not in commun can be eliminated.

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`..8....91........6......8..6.......9..5.2...........2.76...41.........3.9..1..47. 555566677555666777445566777444262788444222888334222888331112998333199999331111199`

- Code: Select all
`Analysis results`

Difficulty rating: 3,8

This Sudoku Jigsaw can be solved using the following logical methods:

57 x Hidden Single

2 x Direct Pointing

1 x Direct Claiming

2 x Direct Hidden Pair

9 x Cage Pointing

5 x Claiming

1 x Naked Pair

1 x Swordfish