Number Place (SUDOKU)
Original Problems
Cool with less clues
Please enjoy our advanced puzzle technology.
The World Hardest Sudoku

I solved this by stupidest method!

NP Generator V2.0

NP Generator V1.0
Small version. This will run on Nintendo DS in 2009.


16x16: less hints, more easy.

The minimum number of hints is currently 56 in 16x16 Sudoku.
The following problems is 56-hint problem. Furthermore this problem is easy as it requires basic tactics and locked candidates only. (2014-11-14)


Compare carefully!


Do you like Gattai?

Diagonal Number Place Programs

Do you know Diagonal Number Place (Diagonal Sudoku)?
Please enjoy new 20 diagonal Number Place problems.

Puzzle Generator Japan

Number Place Problem Generator: Fastest, High Grade, Very Small.
Version 1.0 is simple, small, fast.
New Version 2.0 supports a number of variations.

Source program of Number Place Generator Version 2.0 will be available at Night on December 17 (Japan Standard Time)!

This problem generator makes a problem in 50 millisecond. 18-clue problem is not so diffiluct for this generator. Please enjoy making problems.

Let's Make Number Place -- Elementary course

How to make Automatic Problem Generator.
(Japanese only)

Very long, detailed story.
You could know how to make problem generator.
This online book(free) is quite famous among puzzle programers in Japan.

Enjoy cool problems, made by sudoku problem generator.

18-clues, 100 problems!

Enjoy cool problems



I made this T-shirt.

only 20 clues

100 problems

Do you want this T-shirt.

81 Problems

Last updated on 30 Mar


Find the possible number.

Most puzzlers in Japan use erasable ballpoint pens.
So, erasable ballpoint pens sell quite well.
Do you use a erasable ballpoint pen to solve the printed problems?
Pilot e-GEL (right upper) uni-ball signo erasable(right lower)

Copyright 2006 Hirofumi Fujiwara. All Rights Reserved.