Sudoku Collection : 200 Very Hard Sudoku Puzzles 9X9

Also the puzzle may contain the regions of random (irregular) shape; this variant is called Jigsaw Sudoku

• • Author: Alena Gurin
• • Publisher: Independently Published
• • Publication Date: Aug 20, 2019
• • Number of Pages: 122 pages
• • Language: English
• • Binding: Paperback
• • ISBN-10: 1687465037
• • ISBN-13: 9781687465030