## Twin Corresponding Sudoku

For fans of Killer Sudoku, Samurai Sudoku and other variants

### Twin Corresponding Sudoku

On the website http://www.nrich.maths.org.uk/public/viewer.php?obj_id=5477&part=index&refpage=monthindex.php I found this new interesting Sudoku variant which I spent several days to solve but still could not get the solution.

Perhaps there are some flaws in the puzzle. Can anyone help me to get the solution?
Crusoe

Posts: 2
Joined: 02 November 2006

I think A is solveable and B has multiple solutions.
emm

Posts: 987
Joined: 02 July 2005

The 2 Sudokus are a single puzzle. On their own, they cannot be solved.

The solution of puzzle A is the same as that of puzzle B, but the digits are relabeled. For example, digit 6 in puzzle A is digit 4 in puzzle B.

By checking the corresponding positions of the givens, you can work out most of the digit mapping. For those digits, you can transfer givens and solved cells between the puzzles.

At the end, you need to single coloring move to crack the puzzle.
It has a single solution.

Tip: Use 2 instances of your favorite solver program and set the filters to the corresponding digits.

Ruud
Ruud

Posts: 664
Joined: 28 October 2005

why not relabel the digits of one so that it corresponds to the other......

Super-impose them & solve with singles.........

tarek

tarek

Posts: 2647
Joined: 05 January 2006

### Twin Corresponding Sudoku

Thanks to Ruud, tarek and emm for providing useful suggestions. All of you good guys are very helpful to Sudoku novices like me.
Crusoe

Posts: 2
Joined: 02 November 2006

tarek wrote:why not relabel the digits of one so that it corresponds to the other......

Super-impose them & solve with singles.........

Tarek, I relabel one of the grid and combine the 2 grids together, but I could not solve it with singles only... I need a locked candidate and a turbot fish... Your solver must be able to find singles where human can't...
udosuk

Posts: 2698
Joined: 17 July 2005

It the human who relabelled the grids & super-imposed them & solved them & I had to use what you've mentioned.......I haven't tested it with the solver which is tuned now for MUTANT fish...... should I ?

tarek

tarek

Posts: 2647
Joined: 05 January 2006

For those who are interested to try another example, they can visit Sudokuworld http://games.groups.yahoo.com/group/sudokuworld/ to get it from the folder "Corresponding Sudokus" under the file section. However, registration for Sudokuworld membership is required to access any file. The example in Sudokuworld seems more difficult.
Shintaro

Posts: 35
Joined: 02 November 2006

For those who find it troublesome to join any group, here are the twin puzzles devised by Henry Kwok

Twin A

Twin B

Source: Yahoogroup Sudokuworld http://games.groups.yahoo.com/group/sudokuworld/
Shintaro

Posts: 35
Joined: 02 November 2006

This puzzle (called "Seasonal Twin Sudokus"), posted on the website http://nrich.maths.org/public/viewer.php?obj_id=5518&part=index, is actually another "Corresponding Twin Sudokus" with the cells of one grid filled with letters instead of the usual 9 digits.

Perhaps most people would have already guessed the two hidden words in Twin A.

Merry Christmas!
Shintaro

Posts: 35
Joined: 02 November 2006

Here is another example for this variant. (A little bit more symmetrical and difficult, not so much clues and no given correspondence between the start grids.)

Pyrrhon

Posts: 240
Joined: 26 April 2006

Because Henry Kwok and his avatarian friends are very strong interested in the question who orgins a sudoku variant I like to bring your attention to the fact that the correspondence idea is older then the twin corresponding sudoku variant. So h3lix used it in his Crpytoku. But of course he took his example later down because it was from his point of view too tedious and no fun The difference between both variants is of course the difference between twins and 9 sisters.

Pyrrhon
Pyrrhon

Posts: 240
Joined: 26 April 2006

A "Twin Corresponding Sudokus" puzzle for this Christmas season has been published on the website http://www.ageofpuzzles.com/Collections/TwinSudokus/TwinSudokus.htm under the name of "Twin Sudokus". The cells of one grid are filled with Christmas graphics instead of numbers.

Merry Christmas!
Shintaro

Posts: 35
Joined: 02 November 2006

The same type of twin puzzles has been published on Dr Sam Guo's English-Chinese bilingual website http://www.chinasudoku.com/ with one twin puzzle containing a Chinese seasonal greeting "Merry Christmas and Happy New Year".
Shintaro

Posts: 35
Joined: 02 November 2006

Similar twin puzzles on Otto Janko's reputable German puzzle website
http://www.janko.at/Raetsel/Sudoku/Varianten/999.a.htm with Seasonal greeting: Frohe Weihnachten!
Shintaro

Posts: 35
Joined: 02 November 2006

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