Hard Kakuro Puzzles

Kakuro (also known as "Cross Sums") is a logical puzzle, a mathematical equivalent of crosswords. The puzzle consists of a playing area of filled and empty cells similar to a crossword puzzle. Some black cells contain a diagonal slash from top left to bottom right with numbers in them, called "the clues". A number in the top right corner relates to an "across" clue and one in the bottom left a "down" clue.