dailysudoku.com

keith · Posted: Fri Feb 26, 2016 5:50 pm Post subject: Keith remembers the good old days

This is from an e-mail conversation with a Sudoku co-conspirator:

Yes, it was such fun!

Years ago I noticed Sudoku puzzles in the newspaper. They seemed interesting. But, before I started, I did some research into the mathematics and solution techniques to find they truly are interesting.

So, I started solving them and encountered Marty and the Daily Sudoku site and a lot of people who have long since disappeared.

My first solution breakthrough was what I think they now call a Type 6 UR: A UR overlaid on an X-wing. At the time, it was a new finding!

I then wrote a tutorial on URs that has been referenced tens of thousands of times.

A while later George Woods on Daily Sudoku started pointing out this pattern that if two cells XY are connected by a strong link in Y, they are pincers on X. I took the time to write that down. I am not sure that I invented the name of W-wing, which of course is a tribute to George. That is another tutorial I wrote that has been referenced tens of thousands of times. (I learn things by trying to explain them.)

Some time later, the idea of Medusa Coloring came up. I well remember dropping the puzzle and driving to the local store to buy a box of colored crayons!

Later, I noticed a Medusa chain that was quite short: Two cells XY that are connected such that if one is X, both are X. So add a link on Y on either end and you have pincers on Y, an M-wing! The name is both a play on Medusa and the first letter of my surname.

It was left to others like Nataraj, Ravel, and Asellus to point out that M-wings are quite rich (compared to W-wings) in that they can be asymmetric and also are often closed cycles.

I then wrote another tutorial on remote pairs that is pretty comprehensive for these wings.

http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=2143

It is disappointing to me that to discuss theory and the mildly hard puzzles that are interesting to advanced human solvers using pencil and paper, we now only have sites like "Sudoku Players" where many of the contributors seem to be mostly concerned with more advanced issues and with delivering insults.

I miss the collegial discussions we used to have here. Marty and I seem to be the last men standing!

But, thanks to all of you! It's been a good run.

Keith

Marty R. · Posted: Fri Feb 26, 2016 7:41 pm Post subject:

keith · Posted: Sat Feb 27, 2016 6:19 am Post subject:

Mogulmeister · Joined: 03 May 2007 Posts: 1151

Well thanks for the namecheck Keith. Hope all are well within this forum which has happy memories for me (mostly) !

Apologies - I meant Marty!

enxio27 · Joined: 18 Jun 2012 Posts: 21

I miss the old days, when there was so much activity on the forums, and one could hardly keep up with the new material (especially new variations, gattai, etc.). Lots of people I miss seeing. . .

Mogulmeister · Joined: 03 May 2007 Posts: 1151

Sic transit gloria mundi ..... but I do agree!

Mogulmeister · Joined: 03 May 2007 Posts: 1151

Some of the philosophy discussions were very absorbing, especially as we had a properly multicultural set of presenters

Ghostrider13 · Posted: Thu May 26, 2022 10:04 am Post subject: