OK I have had some requests for puzzles....
Try this:
********4
4*21**356
***54**98
--------------
****86431
6*1***2*9
89423****
--------------
12**59***
953**46*2
7********
Let me know how you do......
Friday, October 14, 2005
Tuesday, October 11, 2005
Math Games:Sudoku Variations
Math Games:Sudoku Variations: "Who made this puzzle? In addition to being the crossword editor of the New York Times, Will Shortz is a puzzle historian, so he did detective work to find the answer. He knew that 'Number Place' puzzles had appeared in Dell Magazines, and went through his collection to find the first. Dell listed no author, but the name Howard Garns always appeared in the contributor's list of any issue containing a 'Number Place' puzzle. Also, Garns' name did not appear in any issue lacking a Number Place, which clinched the identification. Further research revealed that Howard Garns to be a retired architect who created the puzzle at age 74. Howard Garns died in Indianapolis in 1989, and never got a chance to see his creation as a worldwide phenomenon. (Shortz, pers. comm. 2005)
Howard Garns made many Number Place puzzles for Dell, quickly simplifying the rules to those used today -- Fill in the grid so that every row, column, and 3x3 box contains the digits 1 through 9. In April 1984, Japan's puzzle group Nikoli discovered Dell�s Number Place presented it for a Japanese audience in the pages of puzzle paper Monthly Nikolist. Originally named Suuji Wa Dokushin Ni Kagiru, ('the numbers must be single') the puzzle became very popular. Kaji Maki, the president of Nikoli, abbreviated it to Sudoku - (Su = number, Doku = single), and trademarked the name. As the popular grew, competing companies stayed with the non-trademarked name Number Place, or 'nanpure'. Even today, many Japanese puzzle magazines spell out 'Number Place' in English. In the United States and elsewhere, it's called Sudoku ('single number' in Japanese). Thus, japanese-speakers use the English, and english-speakers use the Japanese. Here are two particularly nice Sudoku puzzles under the normal rules. "
Howard Garns made many Number Place puzzles for Dell, quickly simplifying the rules to those used today -- Fill in the grid so that every row, column, and 3x3 box contains the digits 1 through 9. In April 1984, Japan's puzzle group Nikoli discovered Dell�s Number Place presented it for a Japanese audience in the pages of puzzle paper Monthly Nikolist. Originally named Suuji Wa Dokushin Ni Kagiru, ('the numbers must be single') the puzzle became very popular. Kaji Maki, the president of Nikoli, abbreviated it to Sudoku - (Su = number, Doku = single), and trademarked the name. As the popular grew, competing companies stayed with the non-trademarked name Number Place, or 'nanpure'. Even today, many Japanese puzzle magazines spell out 'Number Place' in English. In the United States and elsewhere, it's called Sudoku ('single number' in Japanese). Thus, japanese-speakers use the English, and english-speakers use the Japanese. Here are two particularly nice Sudoku puzzles under the normal rules. "
Saturday, October 08, 2005
Solving Sudoku
Solving Sudoku: "Hidden Singles:
Very frequently, there is only one candidate for a given row, column or 3x3 box, but it is hidden among other candidates.
In the example on the right, the candidate 6 is only found in the middle right cell of the 3x3 box. Since every 3x3 box must have a 6, this cell must be that 6."
Very frequently, there is only one candidate for a given row, column or 3x3 box, but it is hidden among other candidates.
In the example on the right, the candidate 6 is only found in the middle right cell of the 3x3 box. Since every 3x3 box must have a 6, this cell must be that 6."
Friday, October 07, 2005
Sudoku Discussions: A little tip to help solve the puzzles
Sudoku Discussions: A little tip to help solve the puzzles: "Now, at the more tactical level:
1 - if, let's say 3-9, 3-9 appear in the same row (or column), then neither 3 or 9 can occur anywhere else in that row (column). If a pair like that occurs in a 3x3 box, then those values cannot appear anywhere else in that 3x3 box.
If a triple occurs (say 3-6-9) three times in the same column (row, 3x3 box), then those three values cannot occur anywhere else in that column (row, 3x3 box).
NOTE that these numbers must occur without any additional values (e.g, 2-4, and 2-4-7 does not tell you anything - you can't assume anything special about 2 and 4).
I usually mark the values that _can_ occur in an empty entry. Then I look at a row (column, 3x3 box) and see if a value occurs in only one entry (then it has to go there), or if I'm looking at a row or column, if it occurs more than once, but only in a single 3x3 box.
As noted by john mcintosh, three entries that involve three possible numbers (e.g., 1-2, 1-3, 2-3) occurring in a row, column or 3x3 box, also allow you to eliminate those values from occurring anywhere else in that row, column, or 3x3 box.
I hope this hasn't been too confusing. It would be nice if we had a standard notation and terminology as does chess.
I have found that using the techniques above, it has never been necessary to resort to bifurcation. In fact, I've not found a case where bifurcation was helpful (the chain of logic was too long and turned the approach into a form of restricted guessing). It could be that I've just done the wrong puzzles and that eventually I'll hit one where bifurcation is necessary and works, however, I think that would indicate an ill-composed puzzle. "
Sudoku is addictive and helps take your mind off the day
1 - if, let's say 3-9, 3-9 appear in the same row (or column), then neither 3 or 9 can occur anywhere else in that row (column). If a pair like that occurs in a 3x3 box, then those values cannot appear anywhere else in that 3x3 box.
If a triple occurs (say 3-6-9) three times in the same column (row, 3x3 box), then those three values cannot occur anywhere else in that column (row, 3x3 box).
NOTE that these numbers must occur without any additional values (e.g, 2-4, and 2-4-7 does not tell you anything - you can't assume anything special about 2 and 4).
I usually mark the values that _can_ occur in an empty entry. Then I look at a row (column, 3x3 box) and see if a value occurs in only one entry (then it has to go there), or if I'm looking at a row or column, if it occurs more than once, but only in a single 3x3 box.
As noted by john mcintosh, three entries that involve three possible numbers (e.g., 1-2, 1-3, 2-3) occurring in a row, column or 3x3 box, also allow you to eliminate those values from occurring anywhere else in that row, column, or 3x3 box.
I hope this hasn't been too confusing. It would be nice if we had a standard notation and terminology as does chess.
I have found that using the techniques above, it has never been necessary to resort to bifurcation. In fact, I've not found a case where bifurcation was helpful (the chain of logic was too long and turned the approach into a form of restricted guessing). It could be that I've just done the wrong puzzles and that eventually I'll hit one where bifurcation is necessary and works, however, I think that would indicate an ill-composed puzzle. "
Sudoku is addictive and helps take your mind off the day
Sudoku Discussions: A little tip to help solve the puzzles
Sudoku Discussions: A little tip to help solve the puzzles: "First of all, I think of the game as being made up not only of nine rows and columns, but also three 'broad' rows and columns, 3x3 boxes, and little boxes I call 'entries'.
My first step is to examine broad columns from left to right, then broad rows from top to bottom.
Let's say we're looking at a broad column. The 'examination' involves looking at pairs of values that occur in the broad column. If the same number appears twice, that eliminates two broad rows in that broad column. It also restricts us to look at the narrow column that the other two values are _not_ in. If that column has only one empty space, the value goes there. If it has more than one, but the number occurs in enough of the rows crossing the column, the number can be placed uniquely. If neither of these is true, you only know the value has to go in that column.
Each time I can fill in a value, I look at the effect that has on the broad row in which it occurred. I follow this logic until I can't fill that value in anywhere else. Now, following this general scheme, you make (in a sense) one pass through the puzzle's broad columns and rows and you've filled in all the 'easy' values.
Now I look at the boxes that are most-filled-in (usually you'll have at least one box with five values filled in). I look at the values that are missing and see if any of them can occur in only one place in the box. I do the same for the most-filled-in rows and the most-filled-in columns. In particular, look for positions where a most-filled-in column crosses a most-filled-in row at a blank entry.
I will continue to add more insights here.
My first step is to examine broad columns from left to right, then broad rows from top to bottom.
Let's say we're looking at a broad column. The 'examination' involves looking at pairs of values that occur in the broad column. If the same number appears twice, that eliminates two broad rows in that broad column. It also restricts us to look at the narrow column that the other two values are _not_ in. If that column has only one empty space, the value goes there. If it has more than one, but the number occurs in enough of the rows crossing the column, the number can be placed uniquely. If neither of these is true, you only know the value has to go in that column.
Each time I can fill in a value, I look at the effect that has on the broad row in which it occurred. I follow this logic until I can't fill that value in anywhere else. Now, following this general scheme, you make (in a sense) one pass through the puzzle's broad columns and rows and you've filled in all the 'easy' values.
Now I look at the boxes that are most-filled-in (usually you'll have at least one box with five values filled in). I look at the values that are missing and see if any of them can occur in only one place in the box. I do the same for the most-filled-in rows and the most-filled-in columns. In particular, look for positions where a most-filled-in column crosses a most-filled-in row at a blank entry.
I will continue to add more insights here.
Sudoku Discussions: A little tip to help solve the puzzles
Sudoku Discussions: A little tip to help solve the puzzles: "So far this method has worked.
1 After obvious initial entries fill in the blank cells with all allowable numbers.
Now look for a single occurence of any one number:
a) in any row
b) in any column
c) in any of the boxes
when you find a single occurrence then that is the number . Now eliminate that number from the box and row and column.
Then look for another singleton and repeat the process when you find one."
1 After obvious initial entries fill in the blank cells with all allowable numbers.
Now look for a single occurence of any one number:
a) in any row
b) in any column
c) in any of the boxes
when you find a single occurrence then that is the number . Now eliminate that number from the box and row and column.
Then look for another singleton and repeat the process when you find one."
Sudoku Online : Sudoku Helper
Sudoku Online : Sudoku Helper: "To really show what goes on when the script checks your board the Take Step button runs through four tests:
Rows and Columns - fills in the blanks with possible numbers by looking at the existing numbers in each row and column. If only one value is possible its written to the board in a large blue colour.
Each Box - does the same as the first test but it looks to eliminate possibles by checking all the existing numbers in each of the nine 3 by 3 boxes.
Pairs Test. We know we can eliminate numbers if two squares have two identical pairs of numbers. For example, if a row has 3-7 and 3-7 then all other 3s and 7s in that row can be eliminated. Same goes for the box and column.
Box/Line reduction: This is part of the Box tests but I've seperated it so it can be seen. We check the box against the rows and columns that intersect it for each number. See here for more.
The actual tests are slightly more in depth that I have space to explain here. Doubtless there are other strategies that this helper can employ and these will be added in the future. The purpose however is to help you check that your own paper and pencil strategy hasn't introduced any mistakes. "
Sudoku is just too much fun. The real test is to evaluate all the rows, columns, and boxes to eliminate as many candidates as possible.
Rows and Columns - fills in the blanks with possible numbers by looking at the existing numbers in each row and column. If only one value is possible its written to the board in a large blue colour.
Each Box - does the same as the first test but it looks to eliminate possibles by checking all the existing numbers in each of the nine 3 by 3 boxes.
Pairs Test. We know we can eliminate numbers if two squares have two identical pairs of numbers. For example, if a row has 3-7 and 3-7 then all other 3s and 7s in that row can be eliminated. Same goes for the box and column.
Box/Line reduction: This is part of the Box tests but I've seperated it so it can be seen. We check the box against the rows and columns that intersect it for each number. See here for more.
The actual tests are slightly more in depth that I have space to explain here. Doubtless there are other strategies that this helper can employ and these will be added in the future. The purpose however is to help you check that your own paper and pencil strategy hasn't introduced any mistakes. "
Sudoku is just too much fun. The real test is to evaluate all the rows, columns, and boxes to eliminate as many candidates as possible.
The Velvet Blog: Do do sudoku that you do so well
The Velvet Blog: Do do sudoku that you do so well: "Do do sudoku that you do so well
They're all the rage, worldwide. Millions upon millions of people are obsessed with them. And I just don't understand--at all.
They're sudoku, and blame the Japanese for this global craze.
The point of these puzzles is that the numbers 1 through 9 should appear once and only once in any row or column. And I've read a number of explanations of how to do this ... but I just can't. My mind simply goes numb after looking at that grid for more than 10 seconds. For that matter, my mind goes numb after reading the instructions.
I like puzzles, really I do. But I hate these damned things."
They're all the rage, worldwide. Millions upon millions of people are obsessed with them. And I just don't understand--at all.
They're sudoku, and blame the Japanese for this global craze.
The point of these puzzles is that the numbers 1 through 9 should appear once and only once in any row or column. And I've read a number of explanations of how to do this ... but I just can't. My mind simply goes numb after looking at that grid for more than 10 seconds. For that matter, my mind goes numb after reading the instructions.
I like puzzles, really I do. But I hate these damned things."
math_d0rk: SUDOKU!!!!!!!!!!!!!!!
math_d0rk: SUDOKU!!!!!!!!!!!!!!!: "SUDOKU!!!!!!!!!!!!!!!
Sudoku (Japanese: ??, sudoku), sometimes spelled Su Doku, is a placement puzzle, also known as Number Place in the United States. The aim of the puzzle is to enter a numeral from 1 through 9 in each cell of a grid, most frequently a 9�9 grid made up of 3�3 subgrids (called 'regions'), starting with various numerals given in some cells (the 'givens'). Each row, column and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. Its grid layout is reminiscent of other newspaper puzzles like crosswords and chess problems. Sudoku initially became popular in Japan in 1986 and attained international popularity in 2005.
There just isn' enough time in the day to play Sudoku. The real object is a process of elimination. Get rid of as mant numbers as you can and then sift through what you have left.
Sudoku (Japanese: ??, sudoku), sometimes spelled Su Doku, is a placement puzzle, also known as Number Place in the United States. The aim of the puzzle is to enter a numeral from 1 through 9 in each cell of a grid, most frequently a 9�9 grid made up of 3�3 subgrids (called 'regions'), starting with various numerals given in some cells (the 'givens'). Each row, column and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. Its grid layout is reminiscent of other newspaper puzzles like crosswords and chess problems. Sudoku initially became popular in Japan in 1986 and attained international popularity in 2005.
There just isn' enough time in the day to play Sudoku. The real object is a process of elimination. Get rid of as mant numbers as you can and then sift through what you have left.
Rantlust � Blog Archive � Sudoku
Sudoku: "I have never been a fan of crossword puzzles though I have used them as a means to escape boredom during long train journeys across Siberia or Australia. Now, I have found a perfect replacement and I use it even during the daily commute: Sudoku. Even though Sudoku has been around for a while and extremely popular in Japan, it gained worldwide appeal only this year and suddenly, you cannot go to a bookstore without seeing tons of books on it.
The puzzle consists of a 9x9 grid with nine 3x3 subgrids - three per row and column. The puzzle comes with a few of the 81 cells filled in with some numbers. The goal is to fill out the remaining provided each number appears only once per row, column or subgrid. This is based on logic reasoning alone and do not require any mathematical prowess. The numbers could well be replaced with symbols or alphabets. The puzzles are of varying difficulties. "
For an online version, click on the image. Be warned - it's very addictive. I picked up my Sudoku Masters Course and I have not been able to stop playing this stupid game.
The puzzle consists of a 9x9 grid with nine 3x3 subgrids - three per row and column. The puzzle comes with a few of the 81 cells filled in with some numbers. The goal is to fill out the remaining provided each number appears only once per row, column or subgrid. This is based on logic reasoning alone and do not require any mathematical prowess. The numbers could well be replaced with symbols or alphabets. The puzzles are of varying difficulties. "
For an online version, click on the image. Be warned - it's very addictive. I picked up my Sudoku Masters Course and I have not been able to stop playing this stupid game.
Friday, September 02, 2005
Britain, UK news from The Times and The Sunday Times - Times Online
Britain, UK news from The Times and The Sunday Times - Times Online: "The battle begins to win Britain's first Su Doku title
By Michael Harvey
FANS of the logic puzzle that has captured the nation�s imagination will have the chance to pit themselves against the most fiendish Su Doku yet devised at the first National Su Doku Championships.
The puzzle has won millions of addicts since it was introduced to Britain by The Times last November. For the first time players will be in competition with others against the clock. Wayne Gould, who compiles Su Doku for T2 in which it appears five days a week, will produce his most difficult puzzle for the event at The Times Cheltenham Festival of Literature in October.
The Times National Su Doku Championships will follow in the tradition of the Times Crossword competitions and will involve at least one elimination round eligible for all to enter. There will also be a Su Doku junior competition. Hundreds of schools round the country now use Su Doku in lessons.
Carol Vorderman, the Countdown maths wizard and enthusiastic Su Doku solver, hopes to take part as compere or competitor, or both. �I do about five puzzles a day. It�s like an addiction,� she said. �It takes me about 19 minutes to do a fiendish one. I�ll get it down to ten.�
The Times National Su Doku Championships will follow in the tradition of the Times Crossword competitions and will involve at least one elimination round eligible for all to enter. There will also be a junior competition. Hundreds of schools across the country now use Su Doku in lessons. Full details of the championship have yet to be finalised but will be published in The Times.
Within weeks of Su Doku first appearing in T2, it had become a national phenomenon. Newspapers are taking it up from New York to New Zealand via South Africa."
I am right htere with you guys too.
By Michael Harvey
FANS of the logic puzzle that has captured the nation�s imagination will have the chance to pit themselves against the most fiendish Su Doku yet devised at the first National Su Doku Championships.
The puzzle has won millions of addicts since it was introduced to Britain by The Times last November. For the first time players will be in competition with others against the clock. Wayne Gould, who compiles Su Doku for T2 in which it appears five days a week, will produce his most difficult puzzle for the event at The Times Cheltenham Festival of Literature in October.
The Times National Su Doku Championships will follow in the tradition of the Times Crossword competitions and will involve at least one elimination round eligible for all to enter. There will also be a Su Doku junior competition. Hundreds of schools round the country now use Su Doku in lessons.
Carol Vorderman, the Countdown maths wizard and enthusiastic Su Doku solver, hopes to take part as compere or competitor, or both. �I do about five puzzles a day. It�s like an addiction,� she said. �It takes me about 19 minutes to do a fiendish one. I�ll get it down to ten.�
The Times National Su Doku Championships will follow in the tradition of the Times Crossword competitions and will involve at least one elimination round eligible for all to enter. There will also be a junior competition. Hundreds of schools across the country now use Su Doku in lessons. Full details of the championship have yet to be finalised but will be published in The Times.
Within weeks of Su Doku first appearing in T2, it had become a national phenomenon. Newspapers are taking it up from New York to New Zealand via South Africa."
I am right htere with you guys too.
Too good for Fiendish? Then try Killer Su Doku - Times 2 - Times Online
Too good for Fiendish? Then try Killer Su Doku - Times 2 - Times Online
Too good for Fiendish? Then try Killer Su Doku
Leo Lewis in Tokyo
The undisputed grand puzzle master of Su Doku, Tetsuya Nishio, says he has a ‘dreadful challenge’ for Times readers: a worthy successor to the puzzle that has so infuriated and entertained you
THE Japanese have produced more than their fair share of single-minded masters. There are sushi masters who have devoted their lives to the immaculate slicing of raw fish and there are green tea masters who have spent decades honing the art of brewing the perfect cuppa.
And then there is Tetsuya Nishio, the undisputed grand “puzzle master” of Su Doku: a bespectacled fiend from the darkest suburbs of Tokyo who spends his every waking hour devising abominable new ways to torture our brain cells. His only weapon is logic, but, in his own words, “it is a knife that kills”.
His commitment to deviousness is absolute, and he is notorious among the millions of Su Doku fans spread across Japan. When Su Doku champions burst into tears of frustration over the latest “super difficult” puzzle, his is the name they curse out loud. Master Nishio has trained almost all of Japan’s greatest champions and apprentice puzzle masters.
And now, in its first sighting outside Japan, one of the cruellest twists on the basic Su Doku game has reached The Times straight from Nishio’s diabolical stable.
“Of course I have recently read in the Japanese press about the extraordinary Su Doku boom in the UK and I was very happy to see it happening,” says the puzzle master, “but Britain has not had the puzzles for long enough to become fully used to their complexities. This new variation will be a dreadful challenge for you.”
Samunamupure (it translates as “sum number place” and we have named it Killer Su Doku) is a variation that has been evolving among Nishio and his small clan of devoted puzzle students for some years. It is, he says, the perfect example of a next-generation puzzle: it is simple to understand, requires no insider knowledge or training and rewards pure and simple logic.
The digits within the oddly shaped “inner boxes” (marked by dotted lines) must add up to the small number written in the top corner of that box. Apart from that, all the normal Su Doku rules apply. “The really satisfying part,” says Nishio with an evil smirk, “is that you can design a Samunamupure puzzle in a way that you do not need to insert any starting numbers in the grid. I think that will make some people very disturbed.”
The original samunamupure was devised a few years ago by Miyuki Nisawa, one of the puzzle-master’s most accomplished pupils. Under his tutelage she has further sharpened the puzzle’s bite, gradually stretching its difficulty while retaining the appallingly addictive qualities of the Su Doku genre. Others have joined her in honing the puzzles.
Yumiko Meguro, another of the clan, said: “Britain will be surprised and confused by Samunamupure at first, but once you have realised its secret, you will be absolutely lost to it.”
Although Su Doku has its roots outside Japan, it is no surprise that it is here that people such as Nishio have taken the idea to new levels of devotion. Lodged deep in the heart of Japanese culture is the spirit of monozukuri — a concept that translates roughly as “craftsmanship” but implies an obsessive attention to detail. Nishio and his cohorts are in a special class that arises from this concept — of so-called “puzzle-otaku”, or “Su Doku-nerds”.
Nishio spends most of his time in his puzzle studio in Higashimurayama, churning out about 15 puzzles a day. At the moment, he is particularly hard-worked because of a dramatic social phenomenon on the Japanese horizon. “From next year, all the baby boomers born after the Second World War are going to retire at 65, and they are all going to start doing Su Doku to fill their time. The puzzle community and I have to be ready.”
When he does venture outdoors there are certain things he always takes with him. One is a battered, yellowing copy of a 20-year-old American crossword magazine which published the first Su Doku puzzle that Nishio saw. It was included in the magazine as a curio, and never took off in the US. Nishio not only enjoyed the puzzle — as the pencil markings surrounding the grid attest — but gave up his job writing standard logic puzzles to take the Su Doku idea forward.
The other thing that he always carries is a small pad of empty Su Doku grids, “always ready for the next great idea”, he says, taking the pad out and jotting down a secret “work in progress” Su Doku that seems to involve a lot of arrows. “Train, café, bar — you never know when genius will strike.”
Nishio’s mastery of Su Doku has put him at the centre of a huge network of former pupils in Japan and other puzzle masters from around the world. They come to him for advice, for unsweetened criticism of their new offerings, and to seek judgment on the great Su Doku debates of the day.
When one of his apprentices, for example, came up with a new theory that allows certain squares to be filled in earlier than regular logic would allow, the debate raged for months. Eventually, Nishio was won over by the argument, and an explanation of Hamada’s Logic now has pride of place in the front pages of Nishio’s puzzle books.
“Hamada’s Logic makes things fun,” says Nishio. “It gives you the chance to try out some truly mind-bending puzzles that involve a dozen leaps of logic just to fill in a single number.” The master also once engaged in a lengthy debate with Wayne Gould, the compiler behind the Times Su Doku puzzles. Gould complained about a particular Su Doku puzzle of Nishio’s devising, arguing that it required a leap of more than just logic to complete. Nishio argued fiercely against this sacrilege, eventually persuading Gould that it was a puzzle with which Mr Spock would have been perfectly satisfied.
The greatest lesson that Nishio has tried to instill in the members of his stable is that the ideal Su Doku puzzle — of any genre — should involve the solver in a single path of logic. It is perfecting this, he says, that makes it immediately obvious to him which are mediocre Su Doku and which are great.
“I spend every moment thinking about new puzzles and how to make the existing puzzles more interesting. To write a simple puzzle (by his definition, the sort that appears in The Times) takes me around 15 minutes. But a more complicated one will take me as much as two hours.
“The time is spent ensuring that there is a unique solution that can be navigated only by logic.”
As Britain prepares to take on the new challenge of next-generation Su Doku, Japan’s puzzle master offers a simple word of warning: “Do not get too addicted. We can make these puzzles so difficult that it would take a champion six hours to complete one.”
HOW TO PLAY KILLER SU DOKU
KILLER SU DOKU is based on the traditional Su Doku grid with the same rules and digits 1 to 9. Every column, every row and every 3x3 box must contain those digits 1 to 9. But as you can see, in Killer Su Doku there are no traditional clue numbers — only cells linked by dotted lines with a number printed in the top left-hand corner.
The joined squares must be filled with the numbers 1 to 9 that add up to the printed top left-hand figure.
Hints to solve Killer are hidden in the joined squares where only one combination of numbers is possible. In the case of two joined squares, if the printed number is 3, it should be 1 and 2 that go into the squares; if the number is 17, the combination should be 8 and 9. Likewise, in the case of three joined squares, if the printed number is 6, the only combination possible is 1, 2 and 3; if the number is 24, 7, 8 and 9. It is best to start by solving the joined squares with the lower-value printed numbers and then gradually move on to those with larger printed numbers. Killer Su Doku also has a time set by its compiler. See if you can beat the clock.
We think Killer Su Doku is a worthy successor to the puzzle that has infuriated and entertained you since last November when The Times introduced it to Britain. We hope you agree that Killer Su Doku is a deadly new dimension. Good luck.
From today, there is a daily Killer puzzle on the back page of T2, alongside the original simple and Champagne prize Su Doku puzzles.
COMPETITION
WIN A hand-held electronic Su Doku game and The Times Killer Su Doku book.
Complete all five killer puzzles on this page and send your entries to Killer Competition, 1 Pennington Street, London E98 1TT by Tuesday, September 6.
The first ten correct entries drawn will win Su Doku Challenge from Product Creations, an electronic game which comes with 10,000 puzzles, reusable wipe-clean card inserts and LCD display, rrp £34.99 (www.productcreations.com ).
Each winner will also receive a copy of The Times Killer Su Doku book with 100 puzzles to torture and entertain you.
This is a free entry competition. The Editor’s decision is final.
Yahoo... A competition. I am game.
Too good for Fiendish? Then try Killer Su Doku
Leo Lewis in Tokyo
The undisputed grand puzzle master of Su Doku, Tetsuya Nishio, says he has a ‘dreadful challenge’ for Times readers: a worthy successor to the puzzle that has so infuriated and entertained you
THE Japanese have produced more than their fair share of single-minded masters. There are sushi masters who have devoted their lives to the immaculate slicing of raw fish and there are green tea masters who have spent decades honing the art of brewing the perfect cuppa.
And then there is Tetsuya Nishio, the undisputed grand “puzzle master” of Su Doku: a bespectacled fiend from the darkest suburbs of Tokyo who spends his every waking hour devising abominable new ways to torture our brain cells. His only weapon is logic, but, in his own words, “it is a knife that kills”.
His commitment to deviousness is absolute, and he is notorious among the millions of Su Doku fans spread across Japan. When Su Doku champions burst into tears of frustration over the latest “super difficult” puzzle, his is the name they curse out loud. Master Nishio has trained almost all of Japan’s greatest champions and apprentice puzzle masters.
And now, in its first sighting outside Japan, one of the cruellest twists on the basic Su Doku game has reached The Times straight from Nishio’s diabolical stable.
“Of course I have recently read in the Japanese press about the extraordinary Su Doku boom in the UK and I was very happy to see it happening,” says the puzzle master, “but Britain has not had the puzzles for long enough to become fully used to their complexities. This new variation will be a dreadful challenge for you.”
Samunamupure (it translates as “sum number place” and we have named it Killer Su Doku) is a variation that has been evolving among Nishio and his small clan of devoted puzzle students for some years. It is, he says, the perfect example of a next-generation puzzle: it is simple to understand, requires no insider knowledge or training and rewards pure and simple logic.
The digits within the oddly shaped “inner boxes” (marked by dotted lines) must add up to the small number written in the top corner of that box. Apart from that, all the normal Su Doku rules apply. “The really satisfying part,” says Nishio with an evil smirk, “is that you can design a Samunamupure puzzle in a way that you do not need to insert any starting numbers in the grid. I think that will make some people very disturbed.”
The original samunamupure was devised a few years ago by Miyuki Nisawa, one of the puzzle-master’s most accomplished pupils. Under his tutelage she has further sharpened the puzzle’s bite, gradually stretching its difficulty while retaining the appallingly addictive qualities of the Su Doku genre. Others have joined her in honing the puzzles.
Yumiko Meguro, another of the clan, said: “Britain will be surprised and confused by Samunamupure at first, but once you have realised its secret, you will be absolutely lost to it.”
Although Su Doku has its roots outside Japan, it is no surprise that it is here that people such as Nishio have taken the idea to new levels of devotion. Lodged deep in the heart of Japanese culture is the spirit of monozukuri — a concept that translates roughly as “craftsmanship” but implies an obsessive attention to detail. Nishio and his cohorts are in a special class that arises from this concept — of so-called “puzzle-otaku”, or “Su Doku-nerds”.
Nishio spends most of his time in his puzzle studio in Higashimurayama, churning out about 15 puzzles a day. At the moment, he is particularly hard-worked because of a dramatic social phenomenon on the Japanese horizon. “From next year, all the baby boomers born after the Second World War are going to retire at 65, and they are all going to start doing Su Doku to fill their time. The puzzle community and I have to be ready.”
When he does venture outdoors there are certain things he always takes with him. One is a battered, yellowing copy of a 20-year-old American crossword magazine which published the first Su Doku puzzle that Nishio saw. It was included in the magazine as a curio, and never took off in the US. Nishio not only enjoyed the puzzle — as the pencil markings surrounding the grid attest — but gave up his job writing standard logic puzzles to take the Su Doku idea forward.
The other thing that he always carries is a small pad of empty Su Doku grids, “always ready for the next great idea”, he says, taking the pad out and jotting down a secret “work in progress” Su Doku that seems to involve a lot of arrows. “Train, café, bar — you never know when genius will strike.”
Nishio’s mastery of Su Doku has put him at the centre of a huge network of former pupils in Japan and other puzzle masters from around the world. They come to him for advice, for unsweetened criticism of their new offerings, and to seek judgment on the great Su Doku debates of the day.
When one of his apprentices, for example, came up with a new theory that allows certain squares to be filled in earlier than regular logic would allow, the debate raged for months. Eventually, Nishio was won over by the argument, and an explanation of Hamada’s Logic now has pride of place in the front pages of Nishio’s puzzle books.
“Hamada’s Logic makes things fun,” says Nishio. “It gives you the chance to try out some truly mind-bending puzzles that involve a dozen leaps of logic just to fill in a single number.” The master also once engaged in a lengthy debate with Wayne Gould, the compiler behind the Times Su Doku puzzles. Gould complained about a particular Su Doku puzzle of Nishio’s devising, arguing that it required a leap of more than just logic to complete. Nishio argued fiercely against this sacrilege, eventually persuading Gould that it was a puzzle with which Mr Spock would have been perfectly satisfied.
The greatest lesson that Nishio has tried to instill in the members of his stable is that the ideal Su Doku puzzle — of any genre — should involve the solver in a single path of logic. It is perfecting this, he says, that makes it immediately obvious to him which are mediocre Su Doku and which are great.
“I spend every moment thinking about new puzzles and how to make the existing puzzles more interesting. To write a simple puzzle (by his definition, the sort that appears in The Times) takes me around 15 minutes. But a more complicated one will take me as much as two hours.
“The time is spent ensuring that there is a unique solution that can be navigated only by logic.”
As Britain prepares to take on the new challenge of next-generation Su Doku, Japan’s puzzle master offers a simple word of warning: “Do not get too addicted. We can make these puzzles so difficult that it would take a champion six hours to complete one.”
HOW TO PLAY KILLER SU DOKU
KILLER SU DOKU is based on the traditional Su Doku grid with the same rules and digits 1 to 9. Every column, every row and every 3x3 box must contain those digits 1 to 9. But as you can see, in Killer Su Doku there are no traditional clue numbers — only cells linked by dotted lines with a number printed in the top left-hand corner.
The joined squares must be filled with the numbers 1 to 9 that add up to the printed top left-hand figure.
Hints to solve Killer are hidden in the joined squares where only one combination of numbers is possible. In the case of two joined squares, if the printed number is 3, it should be 1 and 2 that go into the squares; if the number is 17, the combination should be 8 and 9. Likewise, in the case of three joined squares, if the printed number is 6, the only combination possible is 1, 2 and 3; if the number is 24, 7, 8 and 9. It is best to start by solving the joined squares with the lower-value printed numbers and then gradually move on to those with larger printed numbers. Killer Su Doku also has a time set by its compiler. See if you can beat the clock.
We think Killer Su Doku is a worthy successor to the puzzle that has infuriated and entertained you since last November when The Times introduced it to Britain. We hope you agree that Killer Su Doku is a deadly new dimension. Good luck.
From today, there is a daily Killer puzzle on the back page of T2, alongside the original simple and Champagne prize Su Doku puzzles.
COMPETITION
WIN A hand-held electronic Su Doku game and The Times Killer Su Doku book.
Complete all five killer puzzles on this page and send your entries to Killer Competition, 1 Pennington Street, London E98 1TT by Tuesday, September 6.
The first ten correct entries drawn will win Su Doku Challenge from Product Creations, an electronic game which comes with 10,000 puzzles, reusable wipe-clean card inserts and LCD display, rrp £34.99 (www.productcreations.com ).
Each winner will also receive a copy of The Times Killer Su Doku book with 100 puzzles to torture and entertain you.
This is a free entry competition. The Editor’s decision is final.
Yahoo... A competition. I am game.
Sudoku - A language of it's Own: Terms defined for all
Sudoku: "The puzzle grid consists of 9 rows (horizontally), 9 columns (vertically) and 9 3x3 boxes. Rows, columns and boxes are all kinds of unit. There are 27 units in a grid. Each unit must contain the digits 1 through 9.
Every unit contains 9 cells. Please don't call the cells "squares", because a box is square and the grid is square. The word "square" only causes confusion.
Three adjoining boxes in a line are a chute. If the chute is horizontal, it is a band. There are 3 bands: top, middle and bottom. If the chute is vertical, it is a stack. There are 3 stacks: left, middle and right. There are 6 chutes in a grid.
The numbers already in the grid are the puzzle's clues. The numbers you add, as a player, are big numbers (as opposed to the small numbers you use temporarily, which are pencilmarks).
When you have an empty cell, the remaining numbers which could go into it according to the rules of the game are the empty cell's candidates.
Boxes are numbered 1 to 9, in this layout:
1 2 3
4 5 6
7 8 9
Rows are numbered 1 to 9, top to bottom.
Columns are numbered 1 to 9, left to right.
A cell is referenced by its row and column number, e.g., r1c1 for the top-left cell, r5c5 for the center cell. "
Well, that pretty much settles it I see boxes termed "regions" and "blocks", but it looks like we are defining the language here. Next, as the culture develops further there will be our own tyoe of currency
Every unit contains 9 cells. Please don't call the cells "squares", because a box is square and the grid is square. The word "square" only causes confusion.
Three adjoining boxes in a line are a chute. If the chute is horizontal, it is a band. There are 3 bands: top, middle and bottom. If the chute is vertical, it is a stack. There are 3 stacks: left, middle and right. There are 6 chutes in a grid.
The numbers already in the grid are the puzzle's clues. The numbers you add, as a player, are big numbers (as opposed to the small numbers you use temporarily, which are pencilmarks).
When you have an empty cell, the remaining numbers which could go into it according to the rules of the game are the empty cell's candidates.
Boxes are numbered 1 to 9, in this layout:
1 2 3
4 5 6
7 8 9
Rows are numbered 1 to 9, top to bottom.
Columns are numbered 1 to 9, left to right.
A cell is referenced by its row and column number, e.g., r1c1 for the top-left cell, r5c5 for the center cell. "
Well, that pretty much settles it I see boxes termed "regions" and "blocks", but it looks like we are defining the language here. Next, as the culture develops further there will be our own tyoe of currency
Sunday, August 28, 2005
A Few Words About Sudoku, Which Has None from the New York Times - This can' be?
A Few Words About Sudoku, Which Has None - New York Times: "A Few Words About Sudoku, Which Has None
By WILL SHORTZ
IT is said that nature abhors a vacuum. As humans we seem to have an innate desire to fill up empty spaces. This might explain part of the appeal of sudoku, the new international craze, with its empty squares to be filled with digits.
Since April, when sudoku was introduced to the United States in The New York Post, more than half the leading American newspapers have begun printing one or more sudoku a day. No puzzle has had such a fast introduction in newspapers since the crossword craze of 1924-25.
A friend in New York reports that his elderly father, a lifelong reader of The Daily News, which does not yet print sudoku, has switched to The Post to get his daily fix. A correspondent reports buying three out-of-town newspapers a day for their sudoku. Truly addicted solvers choose from the dozens of books available, and do the puzzles obsessively, one after another.
Why sudoku? And why now?
The craze started in England last November, when Wayne Gould, a retired judge from New Zealand, persuaded The Times of London to print the puzzle. Judge Gould had seen sudoku in a Japanese puzzle magazine and written a computer program for creating sudoku at any desired level of difficulty.
Japanese puzzle magazines are filled with novel and ingenious logic puzzles. They are as popular in Japan as crosswords are in the United States. But Judge Gould saw two things in sudoku that set it apart: the rules, which can be stated in one sentence, and the size, which does not vary with degree of difficulty.
Every puzzle craze in history has come along at an opportune time, and the same is true of sudoku. The world's first puzzle craze"
I have fell in love with this Sudoku.
By WILL SHORTZ
IT is said that nature abhors a vacuum. As humans we seem to have an innate desire to fill up empty spaces. This might explain part of the appeal of sudoku, the new international craze, with its empty squares to be filled with digits.
Since April, when sudoku was introduced to the United States in The New York Post, more than half the leading American newspapers have begun printing one or more sudoku a day. No puzzle has had such a fast introduction in newspapers since the crossword craze of 1924-25.
A friend in New York reports that his elderly father, a lifelong reader of The Daily News, which does not yet print sudoku, has switched to The Post to get his daily fix. A correspondent reports buying three out-of-town newspapers a day for their sudoku. Truly addicted solvers choose from the dozens of books available, and do the puzzles obsessively, one after another.
Why sudoku? And why now?
The craze started in England last November, when Wayne Gould, a retired judge from New Zealand, persuaded The Times of London to print the puzzle. Judge Gould had seen sudoku in a Japanese puzzle magazine and written a computer program for creating sudoku at any desired level of difficulty.
Japanese puzzle magazines are filled with novel and ingenious logic puzzles. They are as popular in Japan as crosswords are in the United States. But Judge Gould saw two things in sudoku that set it apart: the rules, which can be stated in one sentence, and the size, which does not vary with degree of difficulty.
Every puzzle craze in history has come along at an opportune time, and the same is true of sudoku. The world's first puzzle craze"
I have fell in love with this Sudoku.
Friday, August 26, 2005
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