Oops!

[Richard Pask]

Starting out in Checkers/Draughts Page 78, Diagram 39

Black: men on 12, 16, 20; king on 26
White: men on 23, 27, 28; king on 11
White to play

Continue: … 27-24; 20-27 11-20; 26-19 20-24 (Draw agreed! H Gibson v R Pask 1979) but play on with 19-23 24-31; 12-16 28-24; 16-20. Black wins. No one has pointed this out to me before, and I only discovered it when working on the 'Pocket' section of Logical Checkers, Volume 3 (in progress).

[Bill Salot]

Richard,

It might have done well of entered in a contest. Did that cross your mind?

Bill Salot

[Richard Pask]

Dear Bill,

I confess it did not!

Richard

[George Hay]

Good Catch, Richard Pask! As a reader of Starting Out In Checkers (USA title), I missed it! This correction is destined to be a "Pocket" classic, one of my favorite themes!

--George Hay

[Richard Pask]

9-13 22-18; 10-15 25-22; 6-10 18-14; 10-17 21-14; 15-19 24-15; 11-25 29-22; 8-11 28-24; 1-6 22-18; 13-17 24-19; 11-16 18-15; 16-20 23-18 [As Jim Loy points out, my comment here in CC 'is natural, but works out poorly' might be replaced with 'is natural, but more involved'. However, I still prefer Black]; 4-8 32-28; 7-11 26-22; 17-26 30-23; 11-16 31-26; 3-7 26-22; 6-10 15-6; 2-9 22-17 (varies from 28-24 CR in Lees' Guide); 9-13 19-15; 13-22 18-15; 11-18 18-2; 22-26 2-7; 26-30 7-11 30-26 and we now have a sound version of the pocket theme under consideration!

Jim's comment to me related simply to the worthiness of the 23-18 move; an examination led to the above - a coincidence typical of checkers.

[Alex_Moiseyev]

Richard, something wrong. The run your provided lead us to different position with two extra pieces - white on 14 and black on 5. But this is draw! If you remove them, then yes - red has win. Noone missed anything in game, but perhaps diagram was inaccurate in article (without two extra mens) - just guessing.

BTW. "Opps" comments must be given to white move 18-14 (after 6-10) at earlier stage. Instead, 23-19 would be more accurate to keep initial opening advantage. After 18-14 follow trade 15-19 game is very much even.

AM

[Richard Pask]

Dear Alex,

There is nothing wrong. Both the examples I have given are exactly how I mean them to be: I know that the later position has two extra men and that it is this which makes it sound. The theme, of course, is identical.

In my 'oops!' example, the pocket theme loses, but from the 9-13 22-18; 10-15 run-up, with the extra men, it draws.

In Logical Checkers Volume 3, both positions will be featured.

As Complete Checkers makes clear, 23-19 is of course much more powerful for White than the 18-14 exchange.

[Alex_Moiseyev]

Dear Richard.

thanks for clarification, no more mystery

AM

[Richard Pask]

Dear Alex,

I have often wondered about the terms, 'White to play, what result?'

In the case of the losing 'Oops!' example, I think these terms would work quite well.

Incidentally, the 'Endgame Themes' sections of Logical Checkers are proving to be particularly enjoyable for me, with Boland's brilliant 'Familiar Themes' serving as a great starting point.

Just one example:

Black: 5, 6, 9
White: 21, King 15
By Tom Wiswell (FT Page 58 #3)
White to play and win. (?)

Continue: … 21-17; 9-13 17-14; 13-17 15-18; 17-21 18-22; 6-9?(A) 22-18; 9-13 18-22. White wins.

A: Tom's Complete Guide #3 corrects this with 21-25! 22-29; 6-9 14-10; 9-14 29-25; 14-18. Drawn.

It's not clear whether Ben Boland altered Tom's original setting - thus creating a flaw - or whether it was Tom's error. (The original problem was given in 'Games Digest' January 1938, which I don't have.) Either way, in the Complete Guide Tom states that, just prior to 6-9?, 'This position was actually left as a white win by a noted authority.' Was he referring to Ben or himself?

For the record, for me Tom Wiswell is the greatest problemist of all time.

[chipschap]

BTW. "Opps" comments must be given to white move 18-14 (after 6-10) at earlier stage. Instead, 23-19 would be more accurate to keep initial opening advantage. After 18-14 follow trade 15-19 game is very much even.

It's always interesting to me to see what King's Row has to say. In this case KR thinks any of 23-19, 21-17, 24-20, 24-19, 18-14 or 30-25 are completely even (in ranked order but all with the same evaluation). However what the computer thinks and what is or is not easy to play over the board are entirely different matters, for which we must defer to grandmaster players such as Alex and Richard.

[Richard Pask]

Bob

It sounds like Kingsrow is so powerful - it sees so far ahead that all attacks, no matter how theoretically powerful, peter out - that to it everything is easy!

As indicated in CC, I would arrange the 6 moves in order of strength as follows:

1st: 23-19
2nd: 24-20
3rd: 18-14
4th: 21-17
5th: 30-25 (This is covered in CC via 9-13 23-18; 10-15 26-23; 6-10 30-26)
6th: 24-19

The last-named move was deliberately not covered by me as I felt there was no need: it allows Black to at least equalize with the 11-15 2 for 2. Nonetheless, as a flyer it is the kind of move that players such as Elbert Lowder could readily adopt - no doubt with success: it's sound for a draw and forces crossboard play.

Alex, what would be your ranking of these 6 moves?