Hard Core Hashiwokakero 200 Puzzles for Adults: aka Hashi, Bridges or Ai-Ki-Ai, These Bridges and Islands Logic Puzzles are Fun Brain Games to Keep Your Mind Active.

Hashi Bridges Puzzles Small to Huge: Bridges and Islands Puzzles

Futoshiki Logic Puzzles: 500 Easy to Hard :: Keep Your Brain Young: 11 (Brain Games for Adults)

Calcudoku Logic Puzzles: 500 Easy to Hard (9x9) :: Keep Your Brain Young: 19 (Brain Games for Adults)

Adult Activity Book: 500 Hard Logic Puzzles (Sudoku, Tridoku, Masyu, Hakyuu, Battleships, Fillomino, Suguru, Creek, Numbrix, Binary, Minesweeper and Futoshiki): 26 (Logic & Brain Teasers Series)