Sudoku no 738 (Extreme)

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Sudoku no 737 (Easy)

Our younger son created this puzzle using a Javascript program which he wrote himself:

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Sudoku no 736 (Extreme)

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Sudoku no 735 (Tough / Hard)

13th August 2024:

I wrote my sudoku creation program back in 2012.

Then in 2022 I decided to publish a book of  tough puzzles. I used my program to create puzzles again and again and passed each one to HoDoKu. I stored puzzles with a HoDoKu grade between Hard (1000) and Hard (1999) and discarded the rest. After I had created around 8000 puzzles I had the 400 tough / hard puzzles I needed for my book.

You can buy my book using the advert on this page.

Alternatively, for a chance to win a copy, solve the sudoku below. It has a HoDoKu grade of Hard (1490) so it is typical of the puzzles in my book. Send your answer to me at international_dba@yahoo.co.uk. Do not send me your address at this point. The closing date for entries is 31st October 2024. On 1st November 2024 I will choose one winner at random from all the correct solutions received and ask where to send the book.

The name of the winner and the solution will be published shortly afterwards.

1st November 2024:

This competition is now closed.

3rd November 2024:

The winner is Freddy Vargas from Colombia.

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Sudoku no 734 (Diabolical)

They have been reporting on the TV this morning about a worldwide Microsoft IT outage which is causing disruption at airports, railways, banks etc so I decided to see if I was affected. I switched on my Linux laptop and created the puzzle below. I connected to the Internet and graded it at SudokuWiki then I published it on Google's Blogger platform. Facebook, Twitter and Linkedin are up so I should be able to share it too:

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Sudoku no 733 (Easy)

Our younger son created this puzzle using a Javascript program which he wrote himself:

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Sudoku no 732 (Extreme)

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Sudoku no 731 (Diabolical)

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Sudoku no 730 (Tough)

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Sudoku no 729 (Easy)

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Sudoku no 728 (Extreme)

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Sudoku no 727 (Easy)

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Sudoku no 726 (Diabolical)

Here is a string which you can copy to work on this puzzle online:

030006000000020800050000100000000007040608001700510690620090000900000050803000070  

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Sudoku no 724 (Easy)

If you manage to solve this sudoku, please add a comment below saying how long it took you. You will need a Google account to do this.

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Sudoku no 723 (Tough)

Our younger son created this sudoku using a Javascript program which he wrote himself:

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Sudoku no 722 (Easy)

If you would like me to dedicate a sudoku puzzle to a friend of yours, please add a comment below e.g.

John Smith would like to see a diabolical sudoku puzzle.

You will need a Google account to do this.

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Chess Puzzle no 22

The position below is from Anna Muzychuk versus Zhongyi Tan, FIDE Women's World Cup, 2023, Baku, Azerbaijan. It is white's turn to play. Try to work out how the game continued:

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Sudoku no 720 (Extreme)

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Chess Puzzle no 21

This position is from Tore Colas versus James C Mansson, Hastings 2005. Black to play and checkmate in five moves. There are two possible solutions:

 

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Sudoku no 719 (Tough)

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