Solution to Puzzle no 222

Here is my original version of the solution:

...and here is another version from Baby-Rey Zaballero, a member of my Sudoku Puzzles Facebook group:

Sudoku Puzzle no 222 (Diabolical)

Erick Middleton is a member of my Sudoku Puzzles Facebook group. He wrote a Perl script, which he used to create the puzzle below:

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Solution to Puzzle no 221

Sudoku Puzzle no 221 (Moderate)

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Solution to Puzzle no 220

Sudoku Puzzle no 220 (Tough)

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Solution to Puzzle no 219

Sudoku Puzzle no 219 (Easy)

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Solution to Sudoku no 218

Here is my original version of the solution:

I saw a tweet from Aditya Mathur saying that he had created a sudoku solver using recursion (this is where a program calls itself). I asked him to use it to solve this puzzle. First he keyed the puzzle in:

...then he asked his program to solve it:

Sudoku no 218 (Diabolical)

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Solution to Puzzle no 217

Sudoku Puzzle no 217 (Moderate)

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Solution to Puzzle no 216

Here is the original solution provided by my C program. Andrew Stuart's grader and solver was able to use logic to work out the answer:

Here is one of the online solvers which did not know how to solve the puzzle by logic. Click on the image to enlarge it and bring it into focus if necessary:

Sudoku Puzzle no 216 (Tough)

My C program created this puzzle and I keyed it into Andrew Stuart's grader and solver. It gave the puzzle a grade of Tough. Then I went through the solution with the Take Step button and I saw that the puzzle used a solving method I had never seen before. Andrew Stuart calls it a BUG or Bi-Value Universal Grave. Click on the Solve Online link below to see it in action. Two other online solvers said that it could not be solved by logic. I posted it on my Sudoku Puzzles Facebook group and a couple of the members replied saying that they had finished it. Try it yourself and see what you think:

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Solution to Puzzle no 215

Sudoku Puzzle no 215 (Easy)

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Solution to Puzzle no 214

Sudoku Puzzle no 214 (Diabolical)

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Solution to Puzzle no 213

Sudoku Puzzle no 213 (Moderate)

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Solution to Puzzle no 212

Sudoku Puzzle no 212 (Tough)

Erick Middleton is a member of my Sudoku Puzzles Facebook group. He wrote a Perl script, which he used to create the puzzle below:

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Solution to Puzzle no 211

Sudoku Puzzle no 211 (Easy)

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Solution to Puzzle no 210

Sudoku Puzzle no 210 (Diabolical)

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Solution to Puzzle no 209

Sudoku Puzzle no 209 (Moderate)

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Solution to Puzzle no 208

Sudoku Puzzle no 208 (Tough)

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Solution to Puzzle no 207

Sudoku Puzzle no 207 (Moderate)

Erick Middleton is a member of my Sudoku Puzzles Facebook group. He wrote a Perl script, which he used to create the puzzle below:

Solve online

See answer 

Solution to Puzzle no 206

Here is my original version of the solution:

...and here is another version by Baby-Rey Zaballero, a member of my Sudoku Puzzles Facebook group:

Sudoku Puzzle no 206 (Diabolical)

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Solution to Puzzle no 205

Sudoku Puzzle no 205 (Moderate)

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Solution to Puzzle no 204

Sudoku Puzzle no 204 (Tough)

Erick Middleton is a member of my Sudoku Puzzles Facebook group. He wrote a Perl script, which he used to create the puzzle below:

Solve online 

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Solution to Puzzle no 203

Sudoku Puzzle no 203 (Easy)

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Solution to Puzzle no 202

Sudoku Puzzle no 202 (Diabolical)

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