Additional information
by Alena Gurin (Author)
The book contains 200 Kropki Sudoku puzzles 9x9.
Kropki Sudoku is the variation of the original sudoku. If absolute difference between two digits in neighboring cells equals 1, then they are separated by a white dot. If the digit is a half of digit in the neighboring cell, then they are separated by black dot. The dot between 1 and 2 can be either white or black.