Sven's SudokuPad (web)

Araf Sudoku by Phistomefel

Rules

Normal sudoku rules apply. The grid must be decomposed into different areas. Each cell belongs to exactly one area. Each area contains exactly two clues. The sum of all digits in an area lies between the two clues, but may not reach them. For example, if the clues for an area are 21 and 24, the sum of the digits in the area is 22 or 23. Digits may not repeat within an area.

16 Cups Of Tea by Sumanta Mukherjee

Rules

Normal sudoku rules apply. In cages, digits must sum to the small clue given in the top left corner of the cage. Digits cannot repeat in a cage. Clues outside the grid give the sum of cells along the indicated diagonal. Inequality signs in the grid point to the lower of the two cells involved.

Battlefield Sudoku by Big Tiger

Rules

Normal sudoku rules apply. Consider the first X cells and the last Y cells of a row or column where X is the number in the first cell and Y is the number in the last cell. A clue outside the grid gives the sum of the digits where these groups overlap, or the sum of the digits in the gap between the groups if they don't overlap.

C.T.C. by Prasanna Seshadri

Rules

Normal killer sudoku rules apply (cells in cages must sum to the total given in the top left of each cage). Cage totals have been coded Each letter represents a unique digit. Even numbers within the cages are shaded.

Partial Coded Killer by Scott Strosahl

Rules

Normal sudoku rules apply. Consider the first X cells and the last Y cells of a row or column where X is the number in the first cell and Y is the number in the last cell. A clue outside the grid gives the sum of the digits where these groups overlap, or the sum of the digits in the gap between the groups if they don\'t overlap.

Japanese Sums? by Maho Yokota

Rules

Normal sudoku rules apply. Consider the first X cells and the last Y cells of a row or column where X is the number in the first cell and Y is the number in the last cell. A clue outside the grid gives the sum of the digits where these groups overlap, or the sum of the digits in the gap between the groups if they don\'t overlap.

Arrow Sudoku by Eric Fox

Rules

Normal sudoku rules apply, and digits along arrows sum to the numbers in the circles – some of the 'circles' contain 2-digit numbers.

Six-Pack Linked Sudokus by Genomico (Tom Groot Kormelink)

Rules

This is one large puzzle, consisting of six different variants of 6x6 sudokus, all linked together by circles. A circle is an outside clue for both adjacent puzzles.
Normal 6x6 sudoku rules apply to all sudokus, so each row, column and region must contain 1-6. Outside clues per variant show:
Difference Sudoku: The difference of the first two digits in the corresponding direction.
Outside-2 Sudoku: Must be placed in one of the first two cells in the corresponding direction.
Next-to-6 Sum Sudoku: The sum of all direct neighbours of the digit 6 in the row or column.
Skyscraper Sudoku: The number of visible skyscrapers from that side. Higher skyscrapers block the view of lower ones, size being given by the digit.
MaxAscending Sudoku: The length of the longest series of ascending digits in the corresponding direction. (E.g. the length of a 1-3-6 series is 3.)
First seen odd/even Sudoku: If odd, the first odd number in the corresponding direction; or, if even, the first even number.

Classic Sudoku by Cracking The Cryptic

Rules

Normal sudoku rules apply.

Extra Margins Test Puzzle

Extra Busy Test Puzzle