How do X wings work in Sudoku?

How do X wings work in Sudoku?

Looking at this grid, the player finds two columns with only two possibilities each for number 3. While the cells highlighted in yellow seem to form an X-Wing pattern, the cell in orange prevents the formation of a perfect rectangle since it is not aligned by row.

What does the X mean in Sudoku?

Well, it is just the same as the definition of sudoku (see the relevant page what does sudoku mean for that) with the letter X added to the end – signifying the shape of the two extra regions added to the standard sudoku puzzle to make the sudoku X.

What is an X-Wing pattern?

An X Wing is a technique for removing candidates (pencil marks). It starts with either two parallel rows or two parallel columns. Blocks are not involved here.

What is a finned X-Wing in Sudoku?

A Finned X-Wing is a pattern that is one cell short of being an X-Wing – in other words, two columns that contain a candidate in only two rows, except for one (the fin), and vice versa. The logic behind this technique is that if the fin is not true, the rest of the X-Wing is. Consider the example on this page.

What is an XY chain in Sudoku?

The XY-Chain approach enables you to remove candidates similar to Y-Wing. An XY-Chain is a chain of cells that each contain just 2 candidates. An XY-Chain employs just bivalve cells (similar to Remote Pairs), but the cells might contain arbitrary candidates.

What is a W wing?

A W-Wing is formed by a chain of four cells: A: A cell with two candidates W and X. B: A cell with X as a candidate. C: A cell with X as a candidate.

What are hidden triples in Sudoku?

“Hidden triples” applies when three cells in a row, column, or 3×3 block contain the same three Notes. These three cells also contain other candidates, which may be removed from them.

What is a swordfish in Sudoku?

A Swordfish is a 3 by 3 nine-cell pattern where a candidate is found on three different rows (or three columns) and they line up in the opposite direction. Eventually we will fix three candidates somewhere in those cells which excludes all other candidates in those units.

What is a finned swordfish in Sudoku?

A Finned Swordfish is a pattern that is one cell short of being a swordfish – in other words, three columns that contain a candidate in only three rows, except for one, and vice versa. The logic behind this technique is that if the fin is not true, the rest of the Swordfish is.

How do you spot a naked triple in Sudoku?

Any group of three cells in the same unit that contain IN TOTAL three candidates is a Naked Triple. Each cell can have two or three numbers, as long as in combination all three cells have only three numbers.

What is the knight’s move in Sudoku?

(The knight’s move is 2 along and 1 to the side, as in chess.) 2. Anti-king rules: no two squares that touch either horizontally, vertically or diagonally can have the same digit. (As in, no two squares a chess king can move between in a single move.)

How do you identify the Swordfish pattern in Sudoku?

A Swordfish is a 3 by 3 nine-cell pattern where a candidate is found on three different rows (or three columns) and they line up in the opposite direction.