Sudoku Seventeen

For a sudoku puzzle to have a single solution it needs to have at least 17 clues, although many puzzles in books and magazines typically have as many as 25 clues. You might therefore expect that 17-clue Sudokus are very challenging, and indeed some of them are. In practice they can be tackled with some easily learnt methods which reveal the puzzles to have their own special characteristics. This book continues on from the same author's "World of Sudoku" and explains the methods needed for Sudoku-17 puzzles. Two hundred 17-clue Sudokus, rated according to difficulty, are also included with solutions. The Author, Dr. John Austin, has over 30 years' scientific research experience on the upper atmosphere and has also been involved in the writing of numerous international reports for the Intergovernmental Panel on Climate Change. In recent years, John has broadened his work into popular science and puzzles, and in 2014 he created an internet scientific publishing business Enigma Scientific Publishing, http: //www.enigmascientific.com.