Very Hard Puzzle

Independently published

Very hard puzzle book                            

Delta Stream Media, an imprint of Natural Math

Avoid Hard Work!: And Other Encouraging Problem-Solving Tips for the Young, the Very Young, and the Young at Heart (English Edition)

Brand: St Martins Griffin

Will Shortz Presents the Dangerous Book of Kenken: 100 Very Hard Logic Puzzles That Make You Smarter

Lulu

He/Him/His Sudoku: 200 Very Easy To Hard Puzzles

Createspace Independent Publishing Platform

Sudoku Puzzles - Christmas Edition, Hard to Very Hard: Puzzles + Solutions

Very Hard Jigsaw Sudoku Puzzle Book Vol. 1 (Kindle Scribe Only): 200 Puzzles with Solutions (English Edition)

李旭

Tricky Game                                      

Independently published

Suguru Pocket: 90 Very Hard puzzles 9x9 One Puzzle Per Page (4 x 6 inches in size)

Independently published

Very Hard Samurai Sudoku: 200 Perplexing Puzzles

Jean Bisson

500 Very Hard GIANT Sudoku Book 13