English Chess Forum

At this time last year I opened new topics for each of the Divisions; Division Three (North) as usual taking up most space already.

As Christmas approaches, I have a single room going in Telford for the first weekend if anyone wants it. Msg me directly- first come first served.

Ran into Jim Burnett at Div 3N - dropped/rested - which I presumed meant a very strong White Rose 1 and indeed so it does seem to be.

Still rather short of a real challenge to Guilford of course.

We got what could be a vital 5-3 win against Alba.

IM Jack Rudd wrote: ↑

Sat Nov 11, 2017 11:09 pm

We got what could be a vital 5-3 win against Alba

Only vital if you both end up in Pool D. But likely; so, yes, important. Helped by your impressive early win. I followed that game, live. Felt Andrew Greet was doing OK up to, and including, the win of the exchange. But then it became far less clear, and your pieces became very annoying. Lost the thread around there as I was watching the Rugby. But returned to see you'd swarmed all over him. As I said, impressive.

Think Peter Roberson deserves some sort of prize for messing up Guildfords potential 16-0 weekend Have they managed a perfect weekend before now?
(Varnam might just survive as well but that looks awfully grim to me.).

Great merriment to be found in Jonathan Rogers v. Martin Mitchell - though I suspect the players will have a different word for it. Martin has had a series of forced wins - forced by Stockfish, that is. Meanwhile Jonathan has been running his one remaining piece, a bishop, from square to random square. Poor Martin simply cannot find the correct winning set-up. And after 128+ moves, his chance may have gone. And a further winning chance appeared, then disappeared. An exhausted draw! A good save by Jonathan. It was fearsomely awkward for both players. Match to Spirit of Atticus in any event, something of an upset in itself

David Robertson wrote: ↑

Sun Nov 12, 2017 5:25 pm

Great merriment to be found in Jonathan Rogers v. Martin Mitchell - though I suspect the players will have a different word for it. Martin has had a series of forced wins - forced by Stockfish, that is. Meanwhile Jonathan has been running his one remaining piece, a bishop, from square to random square. Poor Martin simply cannot find the correct winning set-up. And after 128+ moves, his chance may have gone. And a further winning chance appeared, then disappeared. An exhausted draw! A good save by Jonathan. It was fearsomely awkward for both players. Match to Spirit of Atticus in any event, something of an upset in itself

If my memory serves me right the position is drawn if the pawn his passed the 4th rank before the player with the R has forced the defending King off the h and g files. I think the point is that the attacking King needs to regroup via the h4 square in some of the winning lines and it cannot do this if the pawn occupies that square.

Keith Arkell wrote: ↑

Sun Nov 12, 2017 7:24 pm

the position is drawn if the pawn his passed the 4th rank before the player with the R has forced the defending King off the h and g files

F%ck me, Keith. How are we supposed to know this? I was asking myself, while watching, if it were possible to apply principles to the position (only a GM might): namely, a) how should B make progress; and b) how should W organise the optimal defence, given the chance? It was abundantly clear that neither player had very much guidance. In contradiction of your assessment, SF favoured a timely ...h3 where the WB was 'misplaced'. But when the WB was on the b8/h2 diagonal, mostly it was holdable. Frankly,I don't know how - in practice - two players can 'solve the problems. Jonathan stumbled along a precipice; Martin failed to nudge him over. Who can blame them

You meed to keep the bishop in touch with h2 to draw ... I never really understood how you win if your h-pawn hasn't crossed the middle of the board (while remembering reading it in DEM). There's a less well-known draw with an f-pawn too ...

David Robertson wrote: ↑

Sun Nov 12, 2017 8:27 pm

In contradiction of your assessment, SF favoured a timely ...h3 where the WB was 'misplaced'. But when the WB was on the b8/h2 diagonal, mostly it was holdable. Frankly,I don't know how - in practice - two players can 'solve the problems. Jonathan stumbled along a precipice; Martin failed to nudge him over. Who can blame them

It is certainly too complex to fathom over the board, unless the players are aware of a number of principles. You can only play ...h3 if you can follow up with ...h2 without losing the pawn. As Paul Stated, the Bishop needs to be on the h2/b8 diagonal, and in the closing stages of some lines the Bishop gets forced off that diagonal.

I didn't go into detail of all the nuances, but there is no contradiction. In the end the pawn must indeed stroll down the board, but the key manoeuvre is this business of threatening, and in case of some defences, actually employing, the extraction of the Black King from h3, round the back of the Rook on g4, via the h4 square. This is necessary to prevent the White King from sneaking back into the corner. Without this option being available, ie if the pawn is already on h4 before the White King has been driven from the h and g files, then the win cannot be forced as long as the defender maintains the ideal set up.

I have no idea whether I'd be able to put all of this into practice against optimal defence with the clock ticking at the end of a long tiring game!

Well now!

A game that is simultaneously memorable in many ways, whilst virtually impossible actually to remember. 149 moves, after all. If any youth team member misbehaves this season, I shall show him the full game as punishment, trying to reconstruct it without any of the three score sheets.

How did Martin and I think we played the ending? Well, we strongly suspected the ending was a technical win, and of course, it is. We would not have been surprised to learn that our play was sub-optimal on more than one occasion.

Sub-optimal! Ha! More precisely, after move 93, 95, 103, and 105, SF assesses it as -1,000. This must be the best possible example of a position given as -1000 by a computer but where humans would not put too much money on even a seasoned international player actually winning.

Nonetheless, a rocky patch there.

Then, it seems, the defence improves. For the next thirty moves, Black's advantage is not even in double figures. Not that the defence was all that great. At one stage I could have taken the h4 pawn with impunity (move 118). Stockfish is surprisingly kind about this failure, perhaps because the position is a theoretical draw anyway at that precise point. But I had a special reason for not taking it: I was planning to claim a draw under the 50 move rule at move 121, on the ground that nothing had been captured for 50 moves, so I wasn't about to take the h4 pawn even if it was the best move. As everyone then pointed out, there must also have been no pawn moves within the last 50! (I did know that, I insist, but we were so tired ...). So Black's 100....h4 had its advantages after all.

But then again, after my move 137, it jumps back to -1000. Not just taking that h4 pawn on move 118 is not looking so clever now.

But was David actually expecting his team mate to wrap things up at this stage? I expect, not entirely.

I am still struggling to understand it. I now realise that White is simply lost whenever he is boxed into the corner, such that he has to play Bg1 after he is checked. Evidently his king needs to be on g1 so that he can escape to f2 when checked. If I understand Keith correctly, so long as I can do that, then if the pawn is already on h4 (and the bishop is on the h2-b8 diagonal) then it is a draw?

Jonathan Rogers wrote: ↑

Mon Nov 13, 2017 9:59 am

Evidently his king needs to be on g1 so that he can escape to f2 when checked. If I understand Keith correctly, so long as I can do that, then if the pawn is already on h4 (and the bishop is on the h2-b8 diagonal) then it is a draw?

Correct. When the Bishop has been forced from the h2/b8 diagonal onto the a7/g1 diagonal then it is ok for the pawn to advance. So, for example, the position W: Kg1, Bb8; B: R a2, Kh3, ph4 is a draw irrespective of who it is to move. However, place the pawn back on h5 and it is winning, irrespective of who it is to move.

A wonderful example of intuition being of very little value. Either you know this or you don't, and even knowing it is not enough. You need to know why.

Keith Arkell wrote: ↑

Mon Nov 13, 2017 12:24 pm

So, for example, the position W: Kg1, Bb8; B: R a2, Kh3, ph4 is a draw irrespective of who it is to move.

1B6/8/8/8/7p/7k/r7/6K1

Keith Arkell wrote: ↑

Mon Nov 13, 2017 12:24 pm

However, place the pawn back on h5 and it is winning, irrespective of who it is to move.

1B6/8/8/7p/8/7k/r7/6K1