Some puzzles became famous: one for being everywhere, one for having as few clues as a Sudoku can, others for being called the hardest in the world. Here they are, with their story, what My Sudoku makes of them, and a button to play them.
It opens in the app's import window, typed in: tap Import to play it. It joins My puzzles, and your game in progress stays.
Wikipedia
The puzzle that illustrates Wikipedia's article on Sudoku. Seen by millions of readers, it became a favourite of programmers: many tutorials on solving Sudoku by program start with it. It is an easy one: 30 clues, and singles from start to finish.
30 cluesIn My Sudoku: Easy
Techniques it takes: Full House, Naked Single.
Play this puzzleWikipedia · solving algorithms
17 clues, the fewest a Sudoku with one solution can have, and none in the top row, whose answer is 9 8 7 6 5 4 3 2 1. It is made to defeat programs that try digits cell by cell from the top left: they must go through a vast number of combinations before the first row comes out right. That is why Wikipedia's article on solving algorithms shows it. For a person it is no harder than another: singles are enough.
17 cluesIn My Sudoku: Easy
Techniques it takes: Full House, Naked Single, Hidden Single.
Play this puzzle2006 · Arto Inkala
In November 2006 the Finnish applied mathematician Arto Inkala presented it as the world's hardest Sudoku. AI are his initials, and escargot, French for snail, is for the shape he saw in it. It was soon found to be the hardest puzzle known by several of the ways puzzles were rated at the time.
23 cluesIn My Sudoku: Extreme
Beyond the 27 techniques: past the chains, the hints reason by contradiction, supposing a digit and showing that it breaks the rules.
Play this puzzle2007 · JPF
Posted in April 2007 on the Sudoku players' forum by a member called JPF, it is one of the hardest puzzles known: from its start, none of My Sudoku's 27 techniques, chains included, finds a single step. Solving it by logic alone kept the best players busy for months; their solutions came out at the end of 2007 and in 2008.
21 cluesIn My Sudoku: Extreme
Not one of the 27 techniques finds a first step. The hints reason by contradiction, supposing a digit and showing that it breaks the rules; where they find none, they reveal a cell (once on the way to the end).
Play this puzzle2012 · Arto Inkala
since nicknamed Everest
Six years on, in June 2012, Arto Inkala presented another puzzle as the world's hardest, which he said had taken him three months. Newspapers around the world ran it, after The Daily Telegraph. It has since been nicknamed Everest.
21 cluesIn My Sudoku: Extreme
Not one of the 27 techniques finds a first step. The hints reason by contradiction, supposing a digit and showing that it breaks the rules; where they find none, they reveal a cell (once on the way to the end).
Play this puzzleSources: Wikipedia: Sudoku, Wikipedia: Sudoku solving algorithms, SudokuWiki: Escargot, SudokuWiki: Arto Inkala Sudoku, St. Olaf College: the Easter Monster puzzle.
