There are so many Sudoku puzzles that are manufactured by computer programs. Nikoli would like to explain why we keep making Sudoku by hand.

A well-made Sudoku is a pleasure to solve

Nobuhiko Kanamoto – Chief Editor of Nikoli
Have you ever solved a Sudoku puzzle? Do you think you might enjoy solving Sudoku puzzles? Sudoku is a pencil puzzle with simple rules. It’s so beautiful, you might fall in love with it. Perhaps you are fascinated already by Sudoku and are yearning for more. If so, I want to ask, do you know how to recognise a truly good Sudoku puzzle?
Let’s consider a puzzle that has been made using a computer program. If you are a reasonably experienced solver, you might wish to tackle it. You will soon discover that making a start is difficult. There are no cells in which to place a number using straightforward techniques. I’ll show you what to do. Look at box one (upper-left 3×3). There is no 6 in this box, but there are 6s in columns one and three. So, in box one, a 6 can only go in column two, but there are two possible cells. Next, let’s look at 1. In box four (centre-left 3×3) and box seven (bottom-left 3×3) there are no 1s. But there are 1s in rows four, six, seven and nine. In box four, a 1 can only go in row five, and in box seven a 1 can only go in row eight. This means that columns one and three cannot be used for a 1 in box one. The two cells of column two in box one will be occupied by a 1 and a 6. Using this information, you can find the cell that contains an 8 in box one. That’s right – column one, row two. Now, all of the 8s can be placed easily. Once you have discovered how to solve this problem, the puzzle presents no other difficulties.
Can you really say that you enjoy solving this kind of puzzle? I never can. Computer-generated Sudoku puzzles are lacking a vital ingredient that makes puzzles enjoyable – the sense of communication between solver and author. The best Sudoku make you concentrate, but aren’t stressful. They are absorbing, never boring.
Please don’t misunderstand me. I don’t mean that a good Sudoku must be easy. A human sensibility is required for fiendish puzzles, too.
Good Sudoku authors are always considering a solver’s feelings. Can a computer program do this? Can a computer take account of the way a solver thinks?
I am concerned that poor Sudoku, which take no account of solvers, will overwhelm us – and the joy of pure Sudoku will be lost forever.
Sudoku could be your friend for life. I must ask you, therefore, not to touch computer-generated puzzles. Take pleasure in the properly crafted Sudoku puzzles.

Choose wisely

Maki Kaji, the Godfather of Sudoku, the President of Nikoli
We have been supplying hand-made Sudoku puzzles for twenty years. We discovered this puzzle twenty-five years ago in one of Dell’s puzzle magazines, in America. Ever since, we have been absorbed in the never-ending task to create smart and elegant puzzles.
We came up with the rule that digits must be arranged in a symmetrical pattern. We think it’s a beautiful idea. We have nurtured and developed Sudoku. All the time, we have thought more about the solving process than the end results. This is a question of good taste – an issue that computers will never comprehend.
Nikoli’s puzzles are featured in ALL Japanese newspapers and magazines. 100% of them! This is because Japanese solvers prefer our Sudoku puzzles. If you stay with Nikoli, you will come to understand the reasons why. You may invent a program to create Sudoku puzzles, but you will never create Nikoli’s Sudoku puzzles.
Our puzzles are only available through Puzzler Media UK Ltd.
You can see our puzzles in Puzzler Media’s Sudoku magazine and also in The Guardian. Nikoli, Puzzler Media and The Guardian supply puzzles for the true puzzle fan.
Nikoli has created many other hand-made pencil puzzles. It is our dream that these puzzles will be welcomed as warmly as Sudoku by people in the UK.

List of puzzles