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From: Richard Heathfield <rjh@cpax.org.uk>
Newsgroups: rec.puzzles
Subject: Re: BB Sudoku 20250321 very hard
Date: Tue, 1 Apr 2025 06:49:56 +0100
Organization: Fix this later
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On 01/04/2025 01:53, gerson wrote:
> March 21 very hard was the hardest ever for me, whereas the super 
> hard was relatively easy.
> I may have overlooked something. Anybody else?

I missed it, but BB lets you go back in time, so I did just that. 
Yes, it's hard, but I hit a couple of early Swordfishes, and then 
about 12 minutes in (I'm by no means a Sudoku speed king) I found 
myself staring at the top three rows:

  69    7 689 | 5 2 18 |  4  3   16
   4  123  38 | 9 6 18 | 58 25    7
268 1268   5 | 4 7  3 |  9 26 1268

If the first 3x3 has its 1 in the middle, eliminations leave no 
room for a 1 on the third row and lead to all kinds of other 
problems:

  69 7 689 | 5 2 1 | 4 3 1
   4 1   3 | 9 6 8 | 5 2 7
   2 2   5 | 4 7 3 | 9 6 8

With that possibility eliminated the rest more or less cascaded 
into place, but yes, I'd agree that this was harder than your 
average very hard, and yes, the Super Hard came in at under ten 
minutes.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
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