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Sudoku How To Technique: Sword Fish

Taking X Wing to the next level by adding an additional number of valid ROWS and COLUMNS. What you need to look for is a VALID HINT that shows three or less times within a primary ROW or COLUMN that share the same three alternate ROW or COLUMNS. To be valid the HINT cannot show up more than three times within the primary ROW or COLUMN. It can show up more than three times within the alternate ROW or COLUMN or we wouldn’t have anything to eliminate.

Reviewing the example, the primary COLUMNS C3, C4 and C8 have a HINT value of {1}, that share the secondary ROW CONTAINER. Because of that, we are safe to remove the HINT value of {1} anywhere else on the secondary container. Think of the primary container as “safe cells”, and you do not remove hints from those.

This solving method has been categorized as Very Hard Sudoku. Try this and other Very Hard Sudoku solving methods.
Try this Sword Fish Sudoku puzzle.

Puzzle Number: 1280430
Method: SWORD FISH {1} - In Block Type: COLUMN
Found Cell and Hints: s1r1c3 1; s1r2c3 1; s1r1c4 1; s1r2c4 1; s1r4c4 1; s1r2c8 1; s1r4c8 1;
Removing Hints: s1r1c5 1; s1r1c9 1; s1r2c5 1; s1r4c6 1; s1r4c9 1;

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