More Extreme?


Here we begin a review of the second collection of Antoine Alary’s Extreme series, with general comments, a review table, and a checkpoint on the Sysudoku solving on More Extreme 64, a puzzle that is typical of the “generous” variety of Alary puzzles.

Antoine Alary has published two puzzle books under his own name, claiming each to contain “200 of the toughest Sudoku puzzles known to man.” My review differs with this brash claim, but more importantly, it discloses Antoine’s rather unique approach to composing. It’s ambitious and unique, in keeping with the daring Antoine of the back cover, a mathematical logician electronic designer immersed in razor edge sports such as “snowboarding, wakeboarding and mushroom hunting”. You scare me, man.

As usual for the review, I preselected 10 of the 200 puzzles, tracing my solving process with 2-D traces and significant grids. My selection was every 20th puzzle, starting with More Extreme 4. I hope you were successfully introduced to the collection via More Extreme 64, which is represented in the review table. For conventions of the table, see the Reviews page.

More Extreme Table

The table makes clear that Antoine’s claim of “toughest known to man” is a bit overblown, but his puzzles are consistently advanced level. Two invoked a touch ofpattern analysis on my part, but no trials of any kind were required. Among my reviewed collections, KrazyDad’s Insane collection appears to be significantly tougher. And then there’s the established monsters, including two mounted in the Sysudoku trophy room.

This review table is the first featuring the bypass (DB) phase of box marking. I had solved the puzzles before adopting the bypass, and could therefore compare the numbers of box marking clues I found with and without it. In the table, box marking results without the bypass are written below with it. For sure I did better with it, making line marking easier. But in all cases, the final basic solving candidate field after line marking was the same. Only the line marking results with the bypass are included.

Sysudokie readers might be wondering why the number of given clues is omitted from the review table. It’s because it is always the same number, 17. Antoine’s mathematical logic professor may have required him to study the proof that 17 is the minimum number, and in scholarly daring, he has taken this on as a trademark of his puzzles. I can report that, as a composer, Alary consistently provides a route to the solution, which is no small accomplishment with this uniquely limited number of givens.

My bottom line is that my sysudokie readers can well invest in these books. I now have them both, on the strength of the second one, the subject of this review, entitled More Extreme Sudoku, © 2011. The first, Extreme Sudoku, apparently came out in 2010. I don’t understand how I missed it, so I’ll just blame it on Tom Sheldon, Andrew Stuart, Paul Stevens, Will Shortz, SudokuOne, KrazyDad, Max Pitkow, Bob Hanson and Wayne Gould.

In fact, when you get your copy, solve More Extreme 200, the puzzle Antoine singles out as the collection’s toughest. I didn’t want to include the standout toughest in the review, but I will post a checkpoint for you immediately after it. Be prepared for the worst, or best, depending on you.

More 64 DB trThe More 64 bypass trace is typical, with long chains of clues on two numbers. I’m quite pleased that the bypass experience. Miss the path and you are often overwhelmed with candidates.

Speaking of being overwhelmed with candidates, I was annoyed that Antoine includes all number scanned candidates in a keypad format on half of his puzzles. You have to wonder if any Sudoku publication outside of this blog will ever acknowledge the redundancy of keypad marking, and adopt something more useful.

Antoine is excused, though, because his Extreme Sudoku pre-dates the early Sysudoku posts on slink marking, but I do hope that his later editions and collections drop this “helpful” feature. It may be that a good part of the difficulty attributed to his puzzles is just having to get the basic solving done with a minimum of givens, and an inferior starting method. To my way of thinking, providing the candidates, or doing it by computer, is not the answer.

The DB and Box columns of the table divide the collection on basic solving. Puzzles 64 and 184 are especially generous in box marking, while 104, 144, and 164 are downright stingy. Not many clues are added in line marking. We’ll see how this plays out in several puzzles checkpointed in detail, first with the very generous More Extreme 64. The bypass hit two numbers 3 and 9 hard, and the run continued on 9 in slink marking.

More 64 BM tr

More 64 578 wingLine marking is easy, and the resulting grid is liberally populated with slinks and bv, strongly suggesting Medusa coloring . But if you go to your bv map, you are rewarded with a regular 578-wing. The more advanced part is that the victim sees one of the three toxic candidates by forcing chain.

 

 

 

More 64 coloringOr if you happen to miss the XYZ-wing forcing chain, when you get to coloring, you get an easy wrap with two green 8-candidates in c6. In either case, the collapse is immediate.

Let’s do another one.

In the review table, More Extreme 4 rivals a Frank Longo Absolute Nasty IV, or a CrazyDad SuperTough.

 

 

More 4 LMIt starts easily and is also basically generous, but it calls for some advanced artillery.  You can lift out the original clues, do box marking and line marking if you like. From here, see if your advanced solving confirms that review table line. I’ll checkpoint you next post.

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About Sudent

My real name is John Welch. I'm a happily married, retired professor (computer engineering), timeshare traveling, marathon running father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. The blog is about Sudoku solving. It covers how to start, basic solving to find candidates efficiently, and advanced solving methods in an efficient order of battle. It is about human solving methods, not computer solving.
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2 Responses to More Extreme?

  1. Christina HURLEY says:

    I am having difficulty transitioning from Gould’s ‘Extreme’ sudoku to Alary’s ‘Extreme’. Do you know of any puzzles that are extreme and also advise which strategies would be best used to solve them – (possibly giving a clear and simple explanation of the strategy in question, too?) My brain seems to work things out quite well, but am not a scolar, and I generally find explanations of techniques difficult to get my head around. I totally agree with you regarding those annoying numbers printed in Alary’s books. It means that, for me, half of the puzzles can not be attempted, because I don’t use more than 2 numbers in any box (well – very, very rarely – 3).
    Many thanks and kindest regards. Christina

    • Sudent says:

      Cristina, Thanks for a great comment.
      First, don’t rely on author’s and publisher’s ratings. My review didn’t confirm Alary’s to be all that extreme.
      We agree that starting with a cloud of candidates is not a good idea. In fact, Sysudoku’s order of battle limits candidate clutter as much as possible. That’s the reason for slink marking and the bypass. Please read through the posts from the beginning. The earliest ones have been updated to incorporate my latest experiences on how to start. My first year’s posts were written for solvers like you. And do come back with any of my explanations that you find difficult. That is my best hope at getting it right for everybody. As you have done, comment on the problem post. It comes directly to me.
      Be well, Sudent

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