Fill the grid with the digits 1 to 9. The digits represent the height of the skyscraper in each cell. Each row, column and 3x3-box has exactly one of each digit. There are no neighbouring houses with consecutive skyscraper heights. The clues along the edges tell you how many Skyscrapers you can see from that vantage point.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 3. Each row, column, and 3x3 box contains each digit three times. The red arrows indicate that the digit in that cell can't appear in the direction of the arrow.

This is a combination of some sudoku variants.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The grid must fulfill the following rules:

- Sudoku X: The both main diagonals contain each the digits 1 through 9.
- Sum Search Sudoku: The equal signs mark the relations between the sums of the digits of the cages. In cages there can't be the same digit repeated.
- Arrow Sudoku: The digit in a circle is the sum of the digits which are marked with its arrow.
- Ratio Sudoku: The fractions between two cells give the ratio of the digits. For example 2/3 can stand for the following combinations of numbers in the adjazent cells: 2 - 3, 4 - 6, 6 - 9, 3 - 2, 6 - 4 and 9 - 6.
- Wheel Sudoku: The wheels in the grid contain each 4 values. These values will go in the cells the numbers are in. Doing this the wheels must be rotatated to the right position. (Not mirrored or changed the order of the digits.)

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The colored extra-regions must contain each the digits 1 through 9.

In each 3x3 box their is a differet rule to follow:

- Upper left - Consecutive Sudoku: All neighbouring cells with consecutive digits have a colored border.
- Upper centre - Killer <=>: Relation signs represent the relation between the sums of the digits in the sub-regions.
- Upper right - Greater/Less Sudoku: The inequality between each pair of digits must stand correct.
- Centre left - Arrow Sudoku: The digit in a circle is the sum of the digits which are marked with its arrow.
- Centre - Magical square: the sum of any row, any column and both main diagonals in this area is always the same.
- Centre right - Product Sudoku: Digits in a sub-region multiply up to the specified number.
- Lower left - Addoku: Digits in the outside equal the sum of the three numbers of the corresponding row or column in the contigous box.
- Lower centre - Killer: Digits in a sub-region add up to the specified number.
- Lower right - Sum Box Sudoku: First two row of numbers add up to the number formed on the third row.

This combination variant was introduced by Cihan Altay at the 1st Sudoku World Championship.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The colored extra-regions must contain each the digits 1 through 9.

In each 3x3 box their is a differet rule to follow:

- Upper left - Digital Sudoku: Digits are in digital form, as given below.
- Upper centre - Even/Odd Sudoku: Yellow cells must contain odd digits, green cells must contain even digits.
- Upper right - Consecutive Sudoku: All neighbouring cells with consecutive digits have a colored border.
- Centre left - Sum Sudoku (Killer Sudoku): Digits in a sub-region add up to the specified number.
- Centre - Classical Sudoku: No special rule.
- Centre right - Pips Sudoku: Digits are given as pips, like on dominoes or dices, as given below.
- Lower left - Big/Small Sudoku: Red cells must contain small digits (1 - 4), blue cells must contain big digits (5 - 9).
- Lower centre - Greater/Less Sudoku: The inewquality between each pair of digits must stand correct.
- Lower right - Sum Box Sudoku: First two row of numbers add up to the number formed on the third row.

Fill the grid with the digits 1 to 9. The digits represent the height of the skyscraper in each cell. Each row, column and 3x3-box will have exactly one of each digit. The clues along the edges tell you how many skyscrapers you can see from that vantage point.

In each 3x3 box their is a different rule to follow:

- Upper left - Even/Odd Sudoku: Yellow cells must contain odd digits, green cells must contain even digits.
- Upper centre - Min Max Quad Sudoku: The red points in the near of crosses where four cells meet each other show that the cell with the red points is greater then the three other ones. The blue rings in the near of crosses where four cells meet each other show that the cell with the blue ring is smaller then the three other ones.
- Upper right - Arrow Sudoku: The digit in the circle is the sum of the digits which are marked with its arrow.
- Centre left - Difference Sudoku: The numbers between two cells give the difference of the digits.
- Centre - Navigator Sudoku: The arrows show the location of the same number in the previous or next column or row. So for example, the arrow in fifth column means that the same digit is in the sixth column in row 6 - 9.
- Centre right - Greater/Less Sudoku: The inequality between each pair of digits must stand correct.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. Some rows and columns have fractions. The ratio of the connected pairs is 1/2, i. e. there are the following combinations of numbers in the two connected cells: 1 - 2, 2 - 4, 3 - 6 and 4 - 8 or vice versa.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. Some rows and columns have fractions. They represent the ratio of the two ends. For example 3/4 can stand for the following combinations of numbers in the two end cells: 3 - 4, 6 - 8, 4 - 3 and 8 - 6.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The numbers between two cells give the ratio of the digits. For example 3/4 can stand for the following combinations of numbers in the adjazent cells: 3 - 4, 6 - 8, 4 - 3 and 8 - 6.

Fill in the grid so that every row, every column and every 3x3 box contain the digits 1 through 9. Numbers outside the grid gives the position of the maximum of the first three digits.