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## Plain Text Sudoku

This cartoon has at its root, a cartoon from 3/4/2007, called Linear Sudoku. For those that wish to describe a Sudoku puzzle to others, particularly by Email, the best way is to create either an 81 character text string or a 9 strings of size 9, where the dot represents the blank cell in both cases.

The site: Sudoku @ Paulspages permits the selection of a Sudoku puzzle, be it random, non-symmetric or from a gallery of puzzles and from that point, it is possible to export it as a text file as shown to the right of the Board in this Cartoon.

There are several benefits for this format, not the least of which is communicating with another puzzler to verify a difficulty or a solution. For those who are visually impaired, they can employ a software program that converts text to speech, thereby permitting the person to hear what the puzzle elements are, so that they can be solved mentally, or transcribed to a braille-writer for reference.

Now that text messaging is becoming most popular, these text strings can convey a puzzle in a minimum of words. This can be useful in timed competitions, where the winning solution is “texted” over to the contest judges for least time and solution correctness. See, for example:
Sudoku Text Challenge sponsored by the TimesOnline and retrieved June 17, 2008.

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## Sudoku XV

The 3rd World Sudoku Championship (with classic and variant puzzles) has been won by Thomas Snyder of the United States. In second place is Yuhei Kusui of Japan and Jakub Ondrousek of the Czech Republic who placed third. Mr. Snyder also won the Classic Sudoku Championship (no variants), followed by David McNeill of the United Kingdom in second place and Michael Ley of Germany in third place. Team competition results show the Czech Republic in first place, followed by Japan and Germany in 2nd and 3rd place, respectively.

One of the variants shown in the Instruction booklet (First Link in the Downloads Section, a PDF file) for this year’s contenders is known as Sudoku XV. The fewer numerical clues are offset by number pair relationships as sums of 5 or sums of 10. You may use the full force of sudoku analysis to fill in numbers and get the bonus of a neighboring pair value.

There seems to be few puzzle sources for this variant except in Competition instruction booklets. I hope this is temporary. It’s an interesting blend between a limited Kakuro and Sudoku.

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## More 2007 World Sudoku Championship And More Color Sudoku

I’m slowing catching up on the news: On February 3, 2007, The World Puzzle Championship announced the U.S. Sudoku Team Members for the 2007 World Sudoku Championship.
They are:

• Nick Baxter, Captain and Members:
• Grayson Holmes (placed 50th in 1st World Sudoku Championship March 2006),
• Wei-Hwa Huang (placed 2nd),
• Jonathan Rivet,
• Jim Schneider (placed 28th),
• Thomas Snyder (placed 1st),
• Jason Zuffranieri

In the livejournal community called worldpuzzle, there are many details about the upcoming World Championship including instructions (a downloadable pdf file).

There are new kinds of puzzles depicted, which are different from those in 2006. I especially like the puzzle called Paint It Black, which is a blend of a Sudoku Puzzle and a Paint By Numbers Puzzle.

Two Color Sudoku Sites that I noticed are a Color Sudoku Journal Article and a Color Sudoku Solver in MS Excel.

The Journal of Chemical Education is publishing an article called “Chemistry of Art and Color Sudoku Puzzles” by Michael J. Welsh of the Department of Science and Mathematics, Columbia College Chicago, Chicago, IL 60605

The abstract describes what may be a fascinating connection between chemistry and color. Unfortunately a paid subscription to the Journal (\$45 for US Individual) is required for both the full text of the article and the 3 puzzles and solutions file shown in the article.

Quite free is the Color Sudoku Solver via Excel Spreadsheet by Erkki Hartikainen: downloadable xls file. This spreadsheet solver permits you to map the digits and colors in either direction.

One particularly handy feature is the ability to modify colors depending on your own eyes’ ability to distinguish contrasting colors. The color solver is based on a number Sudoku solver by David Ireland.

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## 2nd World Sudoku Championship

This year, From March 28 Through April 1, 2007, The 2007 World Sudoku Championship will take place in Prague, Czech Republic. This championship is sponsored by the World Puzzle Federation. The World Sudoku Championship competitions consist of individual as well as National Team competitions.

It seems like it would be an interesting way to play along (nearly concurrently) if the puzzles are published on that site during the competition. I’m looking forward to it. I missed the 1st World Sudoku Championship and conference held last March 2006. Twenty-two National Teams were represented there.

By downloading the 2.4 MB pdf file via the Sudoku booklet link, you can see the kinds of Sudoku variants that the contestants were exposed to and can solve separately and check your answers with the solution. The game titles are given in the Schedule page, consistent with the instruction booklet.

It’s an amazing collection of variants. Practicing for speed and correctness must be grueling as much before the matches as during competition play.