Useful Sudoku Glossary

Sudoku is an utmost captivating game. It is played by people of any class, region or creed with equal passion. Its benefit is it can not only solved on board or paper, but also online. Moreover, it is in no way related to math; it is purely based on logic. Just because numbers can be identified almost universally, they are used in Sudoku. As such, there are many other Sudoku types, wherein there are no numbers. So those who are afraid of math need not run away from Sudoku, but rather they should solve it and they will have incredible fun. Here are some common terms used in Sudoku which may make solving Sudoku easy.

Cell: A cell in Sudoku is a single square in the grid.

Value: The number which is the solution of a cell.

Active Cell: Active cell is the cell you select in the puzzle. It can be only one. It is highlighted in yellow.

Candidate: A candidate in Sudoku is the probable solutions for a cell at any stage during solving.
Active Candidate: Active candidate is the candidate chosen in an active cell. It is highlighted in green while in Answer Mode. It is marked in brown while in Candidate Mode. Only when “Use Candidates” is checked, candidates become active.

Block: Block is one of the nine inner squares composed of 3×3 small squares, of which Sudoku grid is made up.

Cell Coordinates: Cell coordinates are the combinations of column number/row letter that figures out a cell in an explanation or a hint.

Deduction: Deduction is any one amongst the deductive methods apart from Direct Solves, which include Locked Candidate, Indirect Solve, Naked Pair, Hidden Pair, Naked Triplet, Hidden Triplet, Swordfish, XY-Wing and X-Wing.

Direct Solve: Direct solve is a cell which can be solved easily depending on the cells solved already in its column, row, and/or block. This cell will have either only one probable value (every other value is eliminated) or will be an only cell in the column, row and/or block having a specific value.

Hidden Pair: Hidden pair is a deductive solving method that finds out the two same numbers as candidates of two cells different from each other.

Hidden Triplet: This too is a deductive solving method. It resembles the hidden pair, but includes three cells rather than two.

Indirect Solve: Indirect solve is a cell the solution of which becomes obvious after candidates have been removed (in that cell or somewhere else) with deductive methods. It has either only one probable value (other values are removed) or is the only cell in its column, row and/or block having a specific value.

Locked Candidate: This too is deductive solving method which finds out a value that should appear at the junction of a particular block and column or row.

Naked Pair: Again this is a deductive solving method which finds out two cells in a column, row or block each of which contains the same two candidates, and those candidates only.

Naked Triplet: This deductive solving method resembles the naked pair, but includes three cells rather than two.

Seed: Seed is the solution provided already for some cells. Every Sudoku puzzle begins with some cells already filled in, from where values of other cells can be found out logically.

Swordfish: Again a deductive solving method which is similar to X-Wing, but it considers the interaction among three different columns and cells.

X-Wing: One more deductive solving method that considers the relation between two different columns and rows.

XY-Wing: Another deductive solving method which is a connection that takes place among three cells which create an angle, where each cell has only a couple of values in it.

Extreme Sudoku: This is a kind of Sudoku puzzle wherein two elongated diagonals of the diagram (created a shaded X) should also consist of numbers 1 to 9 upon completion of puzzle.