dailysudoku.com

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Some of my sudoku creations from the British math educational NRICH website and the Age of Puzzles website were used in the Second World Sudoku Championship 2007 at Prague:

1. Ratio Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=4827&part=index&refpage=monthindex.php

2. Intersection Product Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=4903&part=index&refpage=monthindex.php

3. Intersection Sums Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=5018&part=index&refpage=monthindex.php

4. Pole Star Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=5433&part=index&refpage=monthindex.php

5. Twin Corresponding Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=5477&part=index&refpage=monthindex.php

6. Integrated Sums Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=5571&part=index&refpage=monthindex.php

7. Integrated Product Sudoku

http://nrich.maths.org.uk/public/viewer.php?obj_id=5596&part=index&refpage=monthindex.php

8. Duplex Sums Sudoku

http://www.ageofpuzzles.com/Collections/DuplexSumsSudoku/DuplexSumsSudoku.htm

9. Duplex Plex Sudoku

http://www.ageofpuzzles.com/Collections/DuplexPlexSudoku/DuplexPlexSudoku.htm

10. Quadruple Clue Sudoku

http://www.ageofpuzzles.com/Collections/QuadrupleClueSudoku/QuadrupleClueSudoku.htm

The last variant was also used in the Italian National Sudoku Championship 2007.

Please refer to the website http://www.nonzero.it/pdf/indizi.pdf where the variant is called "sudoku a indizi" in Italian.

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

My second Pole Star Sudoku variant (Differenzen-Sudoku) was posted on the NRICH website http://nrich.maths.org/public/viewer.php?rss=1&obj_id=5724&part=index in August 2007.

Another Quadruple Clue Sudoku was published in September 2007 by NRICH http://nrich.maths.org/public/viewer.php?obj_id=5797

My first difference sudoku, Duplex Difference Sudoku (Duplex-Differenzen-Sudoku in German), was published in March 2006 by issue No 38 of Plus magazine http://plus.maths.org/issue38/puzzle/index.html

It used more than one inequality signs as additional clues for solving the puzzle.

Another of my sudoku variant, Minimal Difference Sudoku, was published in October 2007 by NRICH http://nrich.maths.org/public/viewer.php?obj_id=5798

It used only a single inequality sign as additional aid for getting the solution.

I have posted a simple form of twin equivalent Sudoku puzzles called "Twin Chute-swapping Sudoku" on the Nov 2007 NRICH website http://nrich.maths.org/public/viewer.php?obj_id=5870

Both Sudoku puzzles are essentially one and the same puzzle. Each twin can be created from the other by swapping a horizontal/vertical chute or band of blocks with another horizontal/vertical chute or band of blocks.

I have created another simple form of twin equivalent Sudoku puzzles called "Twin Line-swapping Sudoku" for the Dec 2007 NRICH web page http://nrich.maths.org/public/viewer.php?rss=1&obj_id=5907&part=index

Both Sudoku puzzles are essentially one and the same puzzle. Each twin puzzle can be created from the other by swapping the rows/columns within a horizontal/vertical chute of three blocks.

NRICH has also created a beautiful graphic called the "Advent Calendar" on the web page http://nrich.maths.org/content/id/5905/calendar.swf for easy access to some of my past monthly Sudoku puzzles in the run-up to Christmas 2007.

keith · Posted: Sun Jan 06, 2008 1:04 am Post subject: Thank you!

Henry,

Thank you very much for posting these links. I found them very interesting, and challenging. I will be sending the links to my sons' math teachers.

Keith

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Hi Keith,

Thank you for your compliment. I am glad that you think my sudoku puzzles have some educational value.

I hope your sons and his math teachers enjoy the puzzles!

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

I have created the first ever sudoku variant that requires an additional clue from a story for obtaining the solution to the puzzle. I have named my new sudoku variant "Story Sudoku".

I have posted it together with my fairy tale entitled "Fictusia" on Dr Sam Guo's website http://www.chinasudoku.com/

For those readers who like stories and sudoku variants, they may find my "Story Sudoku" new and refreshing.

My new sudoku variant, "Colour Islands Sudoku", is posted on the website http://www.ageofpuzzles.com/Collections/ColorIslandsSudoku/ColorIslandsSudoku.htm

The variant is based in part on the rule of my two board games "Henry's Houses" and "Pseudo-Go". The rule of both board games can be found on the Kadon Enterprise website http://www.gamepuzzles.com/pseudocoup.htm

The rule of both board games is:

"No two pieces of the same colour (or number) may be next to each other in any direction -- horizontally, vertically or diagonally. Each piece must be next to all-different colours (or numbers), different from itself and different from each other. Every fully filled 3x3 area will contain 9 different colours (or numbers)."

My creation "Twin Equivalent Sudoku" is posted on the Jan 2008 NRICH website http://nrich.maths.org/public/viewer.php?rss=1&obj_id=5969&part=index

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Since my "Story Sudoku" is related to the difference sudoku, I take the opportunity here to make a few comments on this special variant.

As the difference sudoku has the peculiar characteristic of having two sets of solution, I jokingly called it "Blindfold Sudoku" in my article on "Corresponding Sudokus" on the NRICH website http://nrich.maths.org/public/viewer.php?obj_id=5439

I published my first difference sudoku, called Duplex Difference Sudoku (Duplex-Differenzen-Sudoku in German), in March 2006 in the issue No 38 of Plus magazine http://plus.maths.org/issue38/puzzle/index.html

The answer of that puzzle was "fixed" by the symbols 1> and 1<The> means the answer in the cell on the left is 1 greater in value than the answer in the cell on the right. Similarly, the symbol 1< indicates that the answer in the cell on the left is 1 less than the answer in the cell on the right.

I could not find any other differerence sudoku on the web until somebody came out with another variation five months later -- in August 2006.

Later on -- in October 2007 -- I "fixed" the answer of the difference sudoku with a single inequality sign instead of multiple inequality signs. This was what I had done with another variant called Minimal Difference Sudoku in October 2007 NRICH http://nrich.maths.org/public/viewer.php?obj_id=5798

The answer of a difference sudoku can also be "fixed" with a single digit in a cell, as what I had done with a variant called "Pole Star Sudoku". There are two such examples on the NRICH website:

http://nrich.maths.org/public/viewer.php?obj_id=5433&part=index&refpage=monthindex.php

http://nrich.maths.org/public/viewer.php?obj_id=5724

Another way to "fix" the answer, as what I had done in a variant called "Constellation Sudoku", is to use a set of starting numbers (a number per star) to fill up some cells containing stars. My first example of such variant was published on the May 2007 NRICH website http://nrich.maths.org/public/viewer.php?rss=1&obj_id=5630&part=index

The same variant was first published as one of the "Puzzles to be solved in Prague -- Good practise" for the Second World Sudoku Championship 2007 on the website http://www.sudoku07.com/main/Puzzles.pdf

My second "Constellation Sudoku" was withdrawn from the Second World Sudoku Championship 2007 at Prague due to longer time required to solve it. It was later published on the website http://www.ageofpuzzles.com/Collections/ConstellationSudoku/ConstellationSudoku.htm

And finally in the "Story Sudoku", I used a clue in a fairy tale to fix the answer of the difference sudoku.

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Another new original creation of mine called "Equation Sudoku" on the Feb 2008 NRICH website http://nrich.maths.org/public/viewer.php?obj_id=5970

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

One more original creation of mine called "LCM Sudoku" on the NRICH website http://nrich.maths.org/public/viewer.php?rss=1&obj_id=6018&part=index

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

My sudoku variant called "All-variables Sudoku" published in April on NRICH website http://nrich.maths.org/public/viewer.php?rss=1&obj_id=6019&part=index

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Please refer to the link http://nrich.maths.org/public/viewer.php?rss=1&obj_id=6224&part=index to have a look at my latest sudoku creation for this month (August) -- Multiplication Equation Sudoku.

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

1. My sudoku variant for this month (September) in http://nrich.maths.org/public/viewer.phprss=1&obj_id=6225&part=index is the Quadruple Clue Sudoku.

2. Other sudoku variants published in the past few months were:

i. Colour Islands Sudoku
in the July issue of http://nrich.maths.org/public/viewer.php?obj_id=6179

ii. Quadruple Clue Sudoku
in the June issue of http://nrich.maths.org/public/viewer.php?obj_id=6113

iii. Twin Corresponding Sudokus
in the May issue of http://nrich.maths.org/public/viewer.php?obj_id=6087

3. Some of my sudoku variants were used in the Czech National Sudoku Championship 2008.

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

My sudoku creation for the October 2008 edition of NRICH in http://nrich.maths.org/public/viewer.php?rss=1&obj_id=6310&part=index is the Addition Equation Sudoku.

keith · Posted: Sun Oct 05, 2008 7:33 pm Post subject:

Henry,

In the Addition Equation Sudoku, you do not need the sum of Row 3. I was able to find the starting grid without it. The resulting puzzle is easy to solve.

By the way, I love your creations!

Best wishes,

Keith

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

My sudoku creation for this month (November 2008) in http://nrich.maths.org/public/viewer.php?rss=1&obj_id=6311&part=index is called the "LCM Sudoku".

For the first time, NRICH uses the creative and innovative idea of flash interactivity for its puzzles.

My first version of "LCM Sudoku" in an earlier issue of NRICH in the link http://nrich.maths.org/public/viewer.php?obj_id=6018 used unknown variables and numbers.

To be more specific, that variant should be called "Algebraic LCM Sudoku".

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

A more challenging version of the LCM Sudoku has been posted this month (November 2008) on the site http://www.chinasudoku.com/

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

My sudoku creation for the December 2008 NRICH http://nrich.maths.org/public/viewer.php?obj_id=6368 is named "Bochap Sudoku" which combines all four arithmetic operations to obtain the solution.

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Back in 2006, only a few sudoku variants were invented as shown in http://www.maa.org/editorial/mathgames/mathgames_09_05_05.html

I can consider myself as one of the pioneers in the invention of sudoku variants outside Japan. After creating sudoku variants for NRICH and other websites for 3 years, it is time now to look back at what I have invented and achieved since 2006.

My first LCM Sudoku variant was invented in April 2008 as shown in http://nrich.maths.org/public/viewer.php?obj_id=6018

A more difficult version of LCM Sudoku was invented in November 2008 as shown in http://www.chinasudoku.com/

A popular sudoku variant invented by me in November 2006 is the Twin Corresponding Sudoku as shown in http://nrich.maths.org/public/viewer.php?obj_id=5477

I also designed it for the Second World Sudoku Championship 2007 at Prague.

wapati · Posted: Sat Jan 24, 2009 2:36 am Post subject:

Yep, I like your puzzles.

Is there something new?

aman · Joined: 29 Dec 2007 Posts: 19 Location: Singapore

Thank you, wapati, for liking my puzzles. If you follow closely and solve every puzzle I published on the NRICH and Age of Puzzles websites since February 2006, there will be nothing new for you, otherwise you will sure to find some interesting new puzzles.

One of my friends just pointed out that he found a so-called "Substitution Twin Sudoku" on one website. The puzzle is similar in every way to my "Twin Corresponding Sudoku" except for its name and its position in a vertical direction. This "new" puzzle was published in 2008 while my puzzle was invented and first published in 2006.

I have to thank that person for liking my "Twin Corresponding Sudoku" so much that he changed its name entirely. It won't be surprising that in the future I shall find other "fans" of mine playing similar jokes on me by pubishing my "Twin Corresponding Sudoku" under other names such as "Replacment Twin Sudoku", "Twin Replacement Sudoku", "Similar Twin Sudoku", "Twin Substitution Sudoku", etc.