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#10 Maki Kaji

Maki Kaji is a president of Nikoli, which introduced “Sudoku” for the first time in Japan. In 1980, he published the first puzzle magazine in Japan. Three years later he established Nikoli, a publishing company of puzzle magazines, and has introduced various puzzles including Sudoku, which is now played in 114 countries around the world. In our interview, we asked him about how interesting Sudoku is and his view of Japanese through Sudoku.


Interview with Maki Kaji

– You entered into a puzzle world after working for publishing and printing companies. What made you to establish Nikoli?


In 1979 when I was working for the publishing company, I got a puzzle magazine from a friend of mine as a souvenir from the USA. Although we had some puzzle books in Japan at that time there was no such Japanese puzzle magazine. One year later I realized no puzzle magazine had come out yet, and thought it would be a good idea to issue it by myself. This is how I started to make puzzles with two of my childhood friends. My experience of having worked for both publishing and printing companies made it easier for me to create the first puzzle magazine although I had never done it before.

At first I had no idea how to promote our puzzle magazines but it turned out there were certain number of puzzle fans in Japan. A year later we constantly received enough puzzles from these fans such as professors, lawyers and students to issue our regular puzzle magazines, which made it possible for us not to make puzzles by ourselves. In 1983 I established our company, Nikoli, as soon as I heard that a major company was planning to issue puzzle magazines in the following year. I had no ambition about the future of our company because we had already had certain number of customers.

–In 1984, you introduced “Sudoku” in your monthly puzzle magazine for the first time. How did you know about Sudoku?


In our magazines, we put puzzles that three of the founders of the company thought to be interesting among puzzles that we received from the readers of our magazines. But I was interested in creating more organized puzzle magazines and started to analyze American puzzle magazines.

I found a quiz that was later named Sudoku by us from one American puzzle magazine. In America, this quiz was called “number place”, and there was only one quiz in one magazine. I initially solved number place from these American magazines, but when I tried to make it by myself I did it. So I started to introduce this puzzle in our magazines. The quality of this puzzle in our magazines was greatly improved as many readers gave us their original quizzes. In 1984 I came up with a word “Sudoku.” It is an abbreviation of a Japanese phrase, which is translated “Only single number is allowed to use in this puzzle.” in English because this puzzle requires to use only numbers from 1 to 9.

– Where do you find fascinating aspects of Sudoku, which is prevailed all over the world? Also what do you think is a main reason for Sudoku to be popular around the world?


Sudoku is easy to play with simple rules and no calculation. All you need is carefulness and imagination. Anyone can enjoy it because Sudoku is a quiz just to put number from 1 to 9 into each box. It takes only 10 to 20 minutes to play one Sudoku quiz and you can play it anywhere. Also you can keep the motivation of playing Sudoku because the more Sudoku you solve the better way of solving it you can find, which is a big difference from crossword puzzles that require specific knowledge to solve them.

Many people take it for granted that you would pay to enjoy yourself in this modern society. However back in the day there were many things you can enjoy with no cost such as playing with stones or chalks and going to mountains. I think you can find real joy from these things. Sudoku also falls in this category because multiple people can play the same quiz by erasing answers. Also you can enjoy playing the same Sudoku because you forget how to solve it as time goes by.

–What is the difference between Nikoli’s Sudoku and Sudoku from other companies?


Since 90% of Sudoku in the world is computer made how interesting it is depends on the skill of programmers who make Sudoku. On the other hand, our Sudoku is all hand made. We have 600 Sudoku creators and each Sudoku has different characteristics depending on who made it. While you solve our Sudoku you can feel as if you enjoyed watching 15 to 20 minute short films. I think it is a primary difference from Sudoku from other companies.

– Where do you find Japanese virtues? Do you have any message that you want to deliver through Sudoku?


You need a balanced sense to solve Sudoku because you can get an answer by looking at boxes at other areas. Americans are ambitions and tend to like success stories. Therefore it is not considered to be good to give up. When I tell Americans that it is effective to take a short break when they have no clue to a Sudoku puzzle that they are working on, Americans are surprised and ask me if it is allowed to give it up and what a balanced sense means. Japanese are exceptional in this kind of balanced sense because they like to improve their skills and prefer to be moderate in many situations.

I used to be asked to deliver lectures at math classes but I have recently been invited to science or art events outside of classes. Although Sudoku is often used as an educational purpose I want you to play Sudoku by finding ways to enjoy it by yourself instead of using it to train your brain. You can satisfy yourself when you find how to solve Sudoku by yourself without being told a way to solve it from someone. I would like to tell the joy of playing through Sudoku.

–How has Sudoku been prevailed in the world?


Sudoku has currently been played in 114 countries. It is a logic puzzle that does not require any language skill. So it can be sold at any countries as a pastime tool. When I started my company playing puzzles was not popular in Japan. However thanks to Sudoku puzzles became popular and they are now fallen into the same category as quizzes, magic and games.

In foreign countries Sudoku initially became popular among older people with having lot of time and people travelling long distance by airplane or train. It is now played by people from different ages from elementary school children to elder people. I am glad to hear that children enjoy playing Sudoku at their math classes. In England and Spain, Sudoku gained popularity by word of mouth. In German, I needed some promotion to introduce Sudoku because German people like things to be organized. Therefore before selling Sudoku books, I introduced Sudoku products such as mug cups and pencils at bookstores, and intentionally created hardback Sudoku books instead of paperbacks. Some Indian high schools have adopted making Sudoku puzzles as a part of curriculum of math classes. In African countries, people play Sudoku by cell phones because paper is expensive there. In hot spots like Syria and Iran, the members of each troop enjoy solving Sudoku at each camp no matter which troop they belong to. Since I heard it I have been thinking it would be cool to make a phrase “Let’s hold pencils instead of weapons.” my theme. Now Sudoku is popular among 80 countries in the world.

–Please let us know about your future plans.


I have created 800 kinds of puzzles so far, 300 of which have currently been played. We have approximately 14 kinds of popular puzzles. I would like to continue to make creative puzzles, which are different from others. Therefore it is important that we do not let you get used to playing our puzzles.

We can offer basic puzzle platforms and allow our passengers to get on and off at these stations whenever they want. We have Sudoku trains, Kakuro (*) trains and many others. These our customers can pick up whichever train they would like to from them. Therefore we need to keep operating various kinds of puzzle trains. And it is my dream to establish Nikoli stations all over the world for these puzzle trains to stop at.

(*) Kakuro is one of the famous puzzles introduced by Nikoli. It is a puzzle to place numbers in blank boxes. You can see more details at

Masaki Kaji

Masaki Kaji is a president of Nikoli whose puzzle magazines introduced one American puzzle under the name of “Sudoku” in Japan for the first time. American puzzle magazine that he got from his friend fascinated him and made him to create a puzzle magazine named “Nikoli” in 1980. He established a puzzle company, Nikoli, with two of his friends in 1983, and started to introduce new puzzles in their puzzle magazines. Nikoli comes from the name of a strong racehorse from Ireland because Kaji is into horse racing. The interest in American puzzle called Number Place led Kaji to introduce it in his magazines by the name of “Sudoku.” It has later gained popularity outside of Japan too due to its simplicity, and has been prevailed among 114 countries. Kaji enjoys visiting many countries all over the world to introduce Nikoli’s puzzles. You can look at Nikoli’s website at

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