Japanese Versions of Sudoku Puzzle games

By now, we have mainly focus on Americanized versions of Sudoku Puzzle Games. Instead of that, this time we will take a look at the Japanese versions of Sudoku. Japanese versions of Sudoku are especially interesting ones.

That is probably the main reason they were published in the magazines and newspapers all over the world. Each version has its own special challenges that are very appealing to various different individuals.

With that said, here is the list of the versions of Sudoku that were developed in Japan:

Sequential Sudoku Puzzles:

Puzzles that are sequentially connected: Sequential puzzles have you solving several 9 x 9 grid Sudoku puzzles at one time. The first puzzle has enough “givens” in it so that it can be solved on its own.

After you have solved the first puzzle some of the numbers are moved from the first solved grid to the grid of the second 9 x 9 puzzle. You will have to work back and forth from one puzzle to the other to successfully solve these sequential Sudoku puzzles.

Overlapping Sudoku Puzzles

A very popular version of Japanese Sudoku are so called multiple overlapping large puzzles, which are generally made up of 9 x 9 grids. These grids deviate from the standard ones (find one and you will see what I am talking about).

It is not uncommon to have one puzzle made up of 20 to 50 standard 9 x 9 grids. Regions of each puzzle will overlap with one another. For instance, two 9 x 9 grids may have 9, 18, or 36 cells that are in common with each other.

You will also find situations where there will be no overlapping areas at all to associate with each other.

Multiple Cells Sudoku Puzzles

There is one thing about these Sudoku Puzzles: They appear quite simple, when you first look at them. Each cell in a 9 x 9 standard puzzle is part of 4 other puzzles instead of just the standard 3 parts - rows, columns, and regions.

In this case numbers that are situated within their region area can not match. You will commonly find these kinds of puzzles printed in color, which makes the identification of the grid area that you are working on more simple and easy.

"Digital Number Place" Puzzles

In 2005 the World Puzzle Championships included this kind of Puzzle called “Digital Number Place”.

Rather than being provided with a “given” most of the cells contained only a partial given. A partial given is a segment of a number where some portions have been drawn as if they are part of a liquid crystal display.

As you can see, the Japanese have developed a vide variety of different Sudoku versions. Try just one of them and you will have an opportunity to spend hours and hours confronting the challenge of solving it.

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Try solving alphabetical Wordokus instead of Sudokus

In my previous post, I was writting about different versions of Sudoku Puzzles available. This time I will tell you about even more versions of Sudoku Puzzles.

Lets first mention couple of more popular Sudoku puzzles, before discussing a Wordoku versions.

There was one especially popular version of Sudoku Puzzle in year 2005. This was a 3 x 3 dimensional grid puzzle invented by Dion Church and then first brought to public by Daily Telegraph. This grid variation rapidly became a hit among those who wanted an ultimate puzzle challenge.

Besides Sudoku puzzle, which are played by using numbers, there also exist alphabetical versions of Sudoku. Instead of numbers, you use letters. You will find these named as "Godoku" or "Wordoku".

It is generally known that these alphabetical versions are especially difficult to solve if you have only a few "givens" to start with.

You will usually find the letters needed for the puzzle beneath the puzzle. The solution of Wordoku is an interesting things by itself as well: The word is spelled out, lined up between the top left bottom and left corners of the grid.

As you can see, this little twist put the puzzle to completely different level. Oftentimes you will be able to guess the word before even solving the puzzle completely.

The Wordoku puzzles are my favourite type of puzzles in general. Try it sometimes and you will find out why! Until next time, have fun and take care!

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Sudoku Puzzle Versions Explained

As mentioned in my previous posts, you can find Sudoku Puzzle Games in many different variations or forms. There is one thing that all these versions have in common.

That is standard that each of the numerals in a particular region has to be unique. One good thing about having so many Sudoku versions to choose from is this: You will never run out of challenges even if you have already solved 1000 puzzles!

If you are beginner to Sudoku here is my advice: begin with the standard grid layout of 9 x 9 before you move on to other variations that are available to you. At this point your aim is to solve the Sudoku puzzle with as little “givens” as you possibly can.

What variations or versions of Sudoku puzzles are available there?

As mentioned above Sudoku puzzle games are normally being solved as a 9 x 9 grid which contains 3 x 3 regions. While this is the most basic grid layout, there are many other versions available as well.

Besides the most standard sudoku version, the following grid layouts are also quite common and makes Sudokus even more challenging:

• 4 x 4 grid with 2 x 2 regions,


• 5 x 5 grid with pentomino regions also known as “Logi-5”,


• 6 x 6 grid with 2 x 3 regions. This grid is used in the World Puzzle Championship,


• 7 x 7 grid with six heptomino regions in addition to a “disjoint” region,


• 9 x 9 grid that normally has nonomino regions.

There also exist larger grid puzzles, for instance a 16 x 16 grid layout puzzle was published by Dell named as "Number Place Challenger". In Japan, Nikoli once published a 25 x 25 grid Sudoku Puzzle.

You will also come across the Sudoku puzzle where the numbers in the main diagonal areas has to be completely different! Another somehow very unique version is called "Gattai 5 Sudoku".

This is a Sudoku with 9 x 9 grids, which at the corner regions convergence into the refined shape of quincunx. In USA this puzzle was named as “Samurai Su Doku”.

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The History of Sudoku Puzzle Games

The history of Sudoku Puzzle Games is presented in this blog post. Lets start with the origin of this game. When considering the name Sudoku, the first country that comes to our mind is Japan.

But Japan is not the country where Sudoku was first popularized. Before going to Japan, this game was already being played in UK and USA. Nonetheless, the Japanese are the ones who came up with the name Sudoku.

It is funny though how Japanese people came up with the name Sudoku. What they did is they took an example from American magazine titled as "Number Place" and then translated it into unique expression with the following meaning:

• Su means number in Japanese language,


• Doku means single unit in Japanese language.

By doing that, this game immediately became very popular in Japan simply because Japanese people prefer number puzzles to word puzzles. This can be explained because of the Japanese language itself: Crosswords just do not function very well.

When was Sudoku Puzzle first published?

The Sudoku puzzle game was first published back in late 1970. This happened in New York and the publisher was "Dell Magazines". This publisher was previously already known as a specialist for logical and ability based puzzle games. This game was published in Maths Puzzles and Logic Problems magazine under the name "Number Place".

Who actually designed this first Sudoku puzzle game is unknown. Nevertheless, it is possible that one of the Dell's puzzle constructors named Walter Mackey could be the person, who designed it.

It was not until yes 1984 when Sudoku was first published in Japan. It appeared in the monthly magazine Nikolist under the name “Suuji wa dokushin ni kagiru”. To translate this in english: “the numbers must be there in only on instance”.

Later on in year 1986 as Sudoku Puzzles were getting more and more popular, Nikoli introduced two different versions of this game. In new versions no more than 30 "givens" were permitted and the grid became proportionate.

Nowadays, Sudoku is being published in all the main stream magazines all over the world, but the trademark of Sudoku is still owned by the Nikoli. Other magazines and publications in Japan use other names for this puzzles though.

The digitalization of Sudoku puzzle games

Sudoku was soon brought to the computer as well. This happened in year 1989 when a programme called DigitHund was produced for the Commodore 64.

This programme was developed by the company named Loadstar/Softdisk Publising and is basically the home computer version of Sudoku puzzle games. People of all ages were able to enjoy this game in a digital version as well.

As you probably know, today you can find Sudoku puzzles in a wide variety of places, among the most popular are perhaps the New York Post and USA Today. Almost every publication out there at some point published a Sudoku game in it.

You will also find this game under the name "Nine Numbers". While Nikoli was able to cash in big time with Sudoku puzzles, the company who invented americanized version of Sudoku was not able to do that.

The Sudoku puzzle arrived at hysteria condition in Japan in 2004 and this hysteria later on spread to the USA and the UK through various national newspapers. The Daily Telegraph uses the name “Sudoku” but you may find it named as “su doku” in other places.

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Search and eliminate external numbers when solving Sudoku puzzles

Regardless of how difficult Sudoku puzzles you are comfortable of solving, there are a couple of Sudoku strategies that can help you find a proper solution more promptly.

If you have been reading my other posts on this blog, then you have already come upon many of them. But what if reading all those Sudoku hints still did not help you solve your Sudokus?

Thus far we have been causally putting in potential numerals, but as you probably know, many of the Sudoku puzzles need you to be completely methodical in order to find and eliminate external numbers.

When you come to a point where you run out of obvious ideas on how to solve the Sudoku, the first thing you should do before anything else is to double check, if you have actually found all the possible numerals that you can put into the puzzle.

Only then I suggest you to go in the unknown territory and start with the methods like bifurcation (we will talk more about this method later).

The initiative step toward accomplishing this is to pencil in all potential numerals in every square. This will take you much less time than you would think to rattle down “can 1 go”, “can 2 go”, “can 3 go” when checking for these numbers in the cell’s region, row, and column.

Therefore, it is always beneficial to repeat one basic tenet of the Sudoku Puzzle, which goes like this: If something holds correct for one element, then it holds true fo other two associated elements as well.

That is it for today. Subscribe to Sudoku hints blog so you will not miss out on my future posts! Take care!

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Use scanning method to find Solutions for Sudoku Puzzles

Today I will briefly explain to you a scanning method that you can use to find solutions for Sudoku Puzzle games. Of course, this method is just one method of solving Sudokus among many, which means that you can still go with other ones, if you find this ineffective.

So how do you use this method? When you begin solving a certain Sudoku, take time to scan the whole puzzle at least once. If you do not manage to find a solution after a couple of attempts, do a couple of scans again.

Take some time as well, just to analyze the puzzle as you work it out. If used properly, scanning can help you to rapidly pick up on a bringing in one or two needed numbers.

Generally speaking, scanning has two primary formulas:

• cross-hatching,


• counting.

Both of these formulas can be used alternately.

At the moment you run out of numerals to put into the cells, you will not be capable to scan the puzzle any longer. When this happens, just begin working zhe puzzle from a logical point of view.

It can be very helpful for you to mark possible numerals in the cells. This can be done by either using subscripts or dots:

1.Subscript marking method

You can use subscript to mark possible numeral into the particular cell. One thing that can make this difficult for you is that many puzzles, for example those in newspapers, are in most cases too small for you to be able to write in the cells.

If you manage to make a larger copy of the Sudoku puzzle so you can read it easier, then you will not have that problem. You can also use a sharp pencil, which will enable you o write fine lines.

2. Dot marking method

The method of dot marking is based on using a pattern of dots. To give you an example: A dot in the topl left corner will signal a one (1) and a dot in the bottom right corner will signal to you a nine (9).

The main advantage of dot marking method is the easiness of using it on the original puzzle.

But make sure to not make any mistakes with dots, since that can led you into confusion. The dots may not be easy to erase to, which means even more confusion for you in case you mix it up to much.

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The connection between Sudoku and Math

Sudoku puzzle game is different from other puzzle games, because Sudoku is has a mathematical structure and also demands a degree of logical thinking in order to figure it out.

The main reason why Sudoku is so difficult to solve is due to so called NP-complete, which is solved on n2 x n2 grids of n x n cells. Since a couple of "givens" are put in the cells on the grids, it will take you some time to clear the Sudoku right.

Sudoku puzzles also has so called game tree that can be pretty large. If a particular game is made with only one possible solution, then solving it can be very hard task to perform. But you can use certain tips to help you figure out your Sudoku much quicker.

The easiest way of discovering the Sudoku puzzle solution is if we call it a graph colouring problem, where the primary goal is to construct a colouring grid in its standard variant of 9 x 9. The entire graph consists out of 81 vertices, with 1 vertex for every single cell that is present on the grid.

We can name each of the vertices with pairs that are ordered and where "x" and "y" are integers, ranging from 1 to 9. Therefore, two individual vertices are names and are also linked by an edge, in case and only in case where the edges correspond.

That means that sooner or later, Sudoku is figured out by imputing an integer, or a number from 1 to 9, to each of the vertices in such way that the vertices, linked by an edge, do not have the same integer imputed to them.

A word about the Latin square

We can also compare the solution of particular Sudoku grid to a Latin square. But you should know however, that there are less solution grids for Sudoku, than there are Latin squares simply because the Sudoku puzzle has another problem: Multiple regions. But despite that, there are endless solution grids for Sudoku puzzle games.

For instance, Bertram Felgenhauer in year 2005 estimated that number to be around 6,670,903,752,021,072,936,960. He gained this number by using logical calculations. The analysis of the number of solution grids was further simplified by Frazer Jarvis and Ed Russell.

It has not yet been calculated how many solution grids there are for the 16 x 16 Sudoku puzzle.

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