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 730 (Tough)

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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 719 (Tough)

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Sudoku no 710 (Tough)

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Sudoku no 703 (Tough)

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

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Sudoku no 701 (Tough)

Our younger son created this puzzle using a Javascript program which he wrote himself. It is right at the bottom of the tough category and only has one hard step:

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Sudoku no 700 (Tough)

Our younger son created this puzzle using a Javascript program which he wrote himself. It is at the bottom of the tough category and only has two tough steps:

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Sudoku no 697 (Tough)

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Sudoku no 690 (Tough)

Our younger son created this puzzle using a Javascript program which he wrote himself. It has only two tough steps so would not have made it into my book.

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Sudoku no 684 (Tough)

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Sudoku no 680 (Tough)

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Sudoku no 672 (Tough)

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

This puzzle has a Hodoku grade of Hard (1038). If you enjoy it there are 400 more in my book, all with a grade between Hard (1000) and Hard (1999). You can order it here.

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Sudoku no 671 (Tough)

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

I used Andrew Stuart's site to check this puzzle and it graded it as 305. The solve path involved two uses of pointing pairs and two of simple colouring. I then ran it through Hodoku, which gave it a grade of Hard (554) so it would not have made it into my book of tough puzzles as they all have a Hodoku grade between Hard (1000) and Hard (1999). You can order it here. This link takes you to Amazon UK. If you go to your local Amazon outlet and search for "tough sudoku" + "andrew reid" you should find it there too.

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Sudoku no 670 (Tough)

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

It has a Hodoku grade of Hard (1054). If you enjoy puzzles like this there are 400 more in my book, which has sudokus with a Hodoku grade between Hard (1000) and Hard (1999). You can order it here.

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Sudoku no 668 (Tough)

This puzzle has a similar grade to the 400 in my book.

Buy my book

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Sudoku no 660 (Tough)

If you prefer solving sudoku on paper, this link will let you buy my first book of puzzles, which is available now.

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

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Sudoku no 656 (Tough)

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

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Sudoku no 655 (Tough)

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

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Sudoku no 652 (Tough)

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