Sudoku types for month January 2013

There will be 4 Classic Sudokus in Round1.
The variations in Round2 in this month are UnTouch Sudoku, XV Sudoku, Irregular Sudoku, Killer Sudoku,
Rules and examples are provided below.

Author

Sudokus for January 2013 are written By Richard Stolk

Classic Sudoku

Place the digits 1 through 9 into the empty cells in the grid so that each digit appears exactly once in each of the rows, columns, and bold outlined 3X3 boxes.

Answer key for the above Sudoku is : 416978325, 327186459

UnTouch Sudoku

Apply Classic Sudoku rules.
Identical digits do not touch each other diagonally.

XV Sudoku

Apply Classic Sudoku rules.
All adjacent cells with two digits summing to 5 are marked by V, while those summing to 10 are marked by X. All possible X and V are marked.

Irregular Sudoku

Every digit from 1 through 7 has to appear exactly once in every row, every column, and outlined regions. Each outlined region has 7 cells and is marked by thick borders.

Killer Sudoku

Apply Classic Sudoku rules.
The sum of digits in cells inside every cage must equal the total given for the cage at the upper left cell. Each digit in the cage must be unique.

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