“Brilliant Mistake”
This is a critical biography of Maki Kaji, the man known as the “Godfather of Sudoku”. (Written in Japanese)

“Puzzle Communication Nikoli Vol.180”
Nikoli is the most advanced pencil puzzle magazine in Japan. The first issue was published in August, 1980.

“C’mon! Easy Sudoku”
75 easy sudoku problems for beginners!

“Sudoku Communication Vol.43”
This book contains about 120 well-crafted sudoku problems. Also, some extra problems and columns.

“Shikaku Collection”
This book contains over 90 Shikaku puzzles.
This is a re-edited version of “Pencil Puzzle Book Shikaku” Vols.1-3.

As already announced the Nikoli smartphone app “SmartNikoli” is discontinued from July 31 2022 (JST) and all operation for this app is terminated.
All membership details of registered members has been deleted.
We wish to express our appreciation and thanks to everybody who have made the operation of SmartNikoli possible during the more than three years since the start in May 2019. First of all we extend a heartfelt thank you to everybody involved in playing our puzzles on SmartNikoli.

This is the end of SmartNikoli, but we are now developing new exciting projects for you to enjoy with our puzzles. Please look forward to news about that as it gets ready.

“Sudoku & Logic Puzzles for Home Vol.4”
“Sudoku & Logic Puzzles for Home Vol.4” contains about 100 puzzles, mainly Sudoku and Logic Puzzle.

“Have a Ball with Pencil Puzzles–Kakuro for Expert 2”
“Have a Ball with Pencil Puzzles–Kakuro for Expert 2” contains over 90 Kakuro puzzles for experts.