Holiday Puzzle #6

So you think you know the rules? This little poser shouldn't bother you for long, but it might make you think twice about how well you know the rules of Chess.

Reportedly played between two Professors of Philosophy ("Justice Good and True" by Heinrich Fraenkel from "Chess Treasury of the Air" edited by Terence Tiller), the question is who won? Or is it a rare case of mutual Checkmate?

White plays 1. Bg2. Is it Checkmate?
Does Black win with 1. ... d5? Or is it mutual Checkmate after 2. cxd6 e.p.?

Professor White played 1. Bg2 and announced Checkmate. Professor Black countered that after 1. ... d5 it is White who is Checkmated, to which Professor White argued that because of 2. cxd6 en passant (with mutual Checkmate!) the pawn was captured on d6 and so never reached d5 protecting its King, 1. ... d5 therefore being an illegal move, played as it was with the King already dead.

You are the arbiter. To whom do you award the game, and why?

Holiday Puzzle #5

Some retrograde analysis. This is a fairly simple starter for this genre of problem, you have to give Black's last move (easy), but for a complete solution, you also have to give the White move that preceeded it.

By Smullyan
What was Black's last move, and the White move that preceeded it?

Holiday Puzzle #4

If the last three were too much, take your thinking cap off for this one.

White to play, mate in 7
Noam Elkies, 2004

Here's a hint: if you can't find the key stop trying, it's easier to solve if you don't!

Holiday Puzzle #3

If you found the mate-in-half problem too easy (or even if you didn't...) try this one. Mate-in-Zero.

From "The Complete Chess Addict"
By Mike Fox and Richard James

Holiday Puzzle #2

Sometimes we all suffer 'Chess Blindness' and miss simple things like mate-in-one. Can you find the mate-in-half here? Yes, the problem is mate in half a move.

From "The Complete Chess Addict"
By Mike Fox and Richard James

Holiday Puzzle #1

A little time out from all that hard analytical work for a little Chess riddle or two.

This one keeps some people amused for hours. There are no tricks; set up your Chessboard in the normal starting position, and in 4 normal, legal Chess moves produce this position (White and Black co-operate 'helpmate' style).

By Mortimer
Reach this position after 4 legal moves

The King In A Rook Box

Or "Do You Know How To Analyse - Part 6", but I was getting bored of that title.

Reinfeld position #986
Black to move

Static analysis: Black has ditched two pawns for active pieces and a King-side assault. White's Queen is unprotected.

Candidate moves:

A. 1. ... Qxh2+ a King hunt.
B. 1. ... Rh6 more pressure on the King.
C. 1. ... Ne2 threatening the Rook and the back rank via the f-file.
D. 1. ... Qe2 threatening pawns and the back rank.

I looked at ... Qxh2+ first, as it should be the easiest to prove or dismiss. I was expecting the latter, but as I started to analyse, I found it has surprisingly long legs...

A. 1. ... Qxh2+ 2. Kxh2 Rh6+ 3. Kg3 Ne2+ 4. Kg4 Rf4+ 5. Kg5

"So far so forced" as they say, the King is boxed in by the Rooks, but where's the coup de grace? At 5 moves out, the position is becoming a little hazy for me - the skill of visualisation which is greatly improved for my tactics practice, but would I play this sac in a real game and hope to find the killer when we get to here? In blitz I'd do it in a blink, but not in a teamleague game!

Reinfeld posisition #986
After 5. Kg5

This is a crux for "knowing how to analyse"; from the first diagram you have to see the second and be sure whether or not there's a (probably quiet) move to continue with. I went on to the next most promising candidate move.

B. 1. ... Rh6 the main idea is
B1. 2. h3 Qxh3+ 3. gxh3 Rxh3#
B2. 2. Nf3 Nd3 3. Qd6 Nxf2# is the smothered mate idea that I missed trying 2. ... Ne2 but
B3. 2. Nf1 Ne2 "etc..." black picks up an exchange, however White remains ahead (+0.7 - Crafty)

C. 1. ... Ne2 another way of trying the ... Qxh2+, ... Rh6# idea, I looked at
C1. 2. Nf1 Rxf2 3. Nd3 with nothing concrete. Crafty says Black is better here but gives
C2. 2. Nf3 Nxg1 3. Kxg1 Rg6 4. Nxe5 Rg5 5. N3c4 Qh3 6. Ne3 Qh5 as 0.00.

D. 1. ... Qe2 I couldn't find a solid continuation, White has a few options and Crafty goes for 2. Qc4 Qxf2 with +2 for White.

The solution is what I suspected I hadn't found for stopping the search too soon. Fred plays (from diagram 2) the elegant

5. ... Rh2 threatening 6. ... h6# 6. Qxf8+ Kxf8 7. Nf3 h6+ 8. Kg6 Kg8 threatening 9. ... Rf6# 9. Nxh2 Rf5 threatening 10. ... Rg5# 10. exf5 Nf4#

While Crafty is more direct

5. ... Rff6 threatening 6. ... Rfg6# 6. Qxf8+ Kxf8 7. Kg4 Rfg6+ 8. Kf3 Nxg1#.

Do You Know How To Analyse? Part 5

Another quick one I did at lunchtime. I selected it by scanning the solutions for a long variation in one of the last couple of chapters, so I only had a vague recognition of the position. The last few chapters aren't categorised by motif, just things like 'Surprise Moves' - having learnt the motifs in the earlier chapters, part of the excercise is to identify the motif for yourself.

Reinfeld position #811
Black to move

Static analysis: Black has sacrificed a piece for the attack, opening the h-file.

Candidate moves:

A. ... Rh1+
B. ... gxf2+
C. ... Bxf2+
D. ... Nxe4
E. ... Ng4
F. ... Nd4
G. ... Qe7
H. ... Qd7
I. ... d5

F, G, and H with the idea of bringing more pieces to the attack (i.e. in conjunction with 0-0-0) look too slow under the circumstances and ...d5 needs another big idea fast. ... Rh1+ is looking for a Suicide Squad idea but the f2 pawn and time it will take the Queen to get to the h-file put paid to that.

Trying B and C directly lead to positions where Black has exchanged two minors for a Rook and not much promise (though Crafty gives ... gxf2 about -0.6) so my first try was 1. ... Nxe4.

D1. 1. ... Nxe4 2. Bxd8 the basic test of the idea 2. ... Bxf2+ 3. Rxf2 gxf2+ 4. Kf1 Rh1+ 5. Ke2 Rxd1 6. Kxd1 f1/Q+

First I'd tried 2. ... gxf2+ until I realised the pawn promotion idea was better and played the captures the other way around. Black is material ahead after 7. ... Kxd8 but simply

D2. 1. ... Nxe4 2. dxe4 and Black, already two pieces down, has nothing.

Candidate move E has the same idea without exposing the Knight to capture.

E. 1. ... Ng4 2. Be3 (2.Bxd8 is just a better version of D1) 2. ... Nxe3 3. fxe3 (or else Black simply wins the exchange) 3. ... Bxe3+ and we're effectively back in D1 with more material.

Not exactly an exhaustive analysis (in about 20 minutes) but the position was basically cracked that way instead of 'searching for a combo'. Fred's solution:

1. ... Ng4 2. Bxd8 Bxf2+ 3. Rxf2 gxf2+ 4. Kf1 Rh1+ 5. Ke2 Rxd1 6. Nfd2 Nd4+ 7. Kxd1 Ne3+ 8. Kc1 Ne2#.

All very pretty but hardly forced, and I wonder if it's a good thing that I was on the same track as Fred... here's what Crafty says:

1. ... Ng4 2. d4 gxf2+ 3. Rxf2 f6 4. Bh4 Nxd4 5. b4 Nxf3+ 6. Qxf3 Rxh4 7. bxc5 Nxf2 8. Qxf2 9. Bb5+ c6 10. Nc3 Rf4 (-2.5).

All a bit computer-like, but 2. d4 should probably have been the first defense a human should consider too!

Do You Know How To Analyse? Part 4

This is the first 'simpler' position I picked to analyse. I chose it because when I attempted it as a tactical excercise (overloading) I found some interesting ideas but not Fred's solution, and on subsequent passes, I still didn't remember Fred's solution mainly because it doesn't seem to be a forced variation.

Reinfeld position #422
White to move

Here's what I came up with in about half an hour.

Static analysis - White is down two pawns for far superior development and an attack.

Before listing candidate moves, I wanted to check Black's counter-play so by null-moving White we can see that 1. ... Qa1+ 2. Kh2 leaves the Black Queen attacked and compelled to move - handy if for example Re8 is attacked at the same time.

Candidate moves.

A. 1. Qh5 - mating attack
B. 1. Ng4 - double attack on the Rook and Queen
C. 1. Nd5 - triple attack, Nxc7xc8 also threatened
D. 1. Rh6 - to break up the castle, mating attack
E. 1. Nf5 (or N-other) - discovered mate threat
F. 1. Rxh7 - mating attack

My analysis, starting with the variations that look simplest:

A. 1. Qh5 Qg6 2. N?? Rxe2 3. Qxe2 Qe6 Black looks ok - Crafty gives White a small (+1.5) advantage.

D. 1. Rh6 gxh6 White has nothing more, Black is winning. Actually crafty gives Black a winning Queen ending at depth 14 - 2. Nd5 Qa1+ 3. Kh2 Rxe2 4. Qxe2 Nd7 5. Qe8+ Kg7 6. Nxc7 Rb8 7. Nd5 Qd4 8. Bxb8 Nxb8 9. Qxc8 Qxd5 10. Qxb8 Qxa2

F. 1. Rxh7 Kxh7 2. Ng4 Qa1+ 3. Kh2 - the Queen is not attacked in this line, Black is winning. Crafty gives 2. Nd5 but agrees with the basic idea for Black.

E. 1. Nf5 (or other, ie. 1. Nc2 would have the idea of preventing Qa1+, which we've already demonstratred is unnecessary) 1. ... Rxe2 2. Nh6+ gxh6 3. Rxh6 Qa1+ etc, Black is winning.

So to the crucial variation - I didn't analyse 1. Ng4 due to time constraints and because at sight it's a 'lesser version' of 1. Nd5, that is, if Nd5 doesn't work 1.Ng4 probably won't either and White will be playing the best move so far 1.Qh5.

Black has two replies to 1.Nd5, 1. ... Qc6 and 1. ... Qd8.

C1. 1. Nd5 Qc6 2. Nxc7 the Knight should escape after Nxa8 netting a whole Rook and if something like 2. ... Na6 3. Qxc6 wins lots of material. Crafty is at about +4 after 2. ... Rxe2 3. Qxe2 g5 4. Be5 Nd7 5. Nxa8 Qe6 6. f4 Nxe5 7. fxe5 Qg4 8. Qd3 Qf5 9. Qd8+ Kg7 10. Kh2 Be6.

C2. 1. Nd5 Qd8 2. Bxc7 Qd7 3. Qf5 White is trying to deflect the Black Queen from defending the Rook 3. ... h6 4. Rxe8+ Qxe8 5. Ne7+ Qxe7 6. Qxc8+ Kh7 7. Qxb7 and White is better - although there's still some work to be done for the full point.

Fred's single variation solution is:

1. Nd5 Qd8 2. Bxc7 Qd7 3. Qg4 Re6 this is the plausible but unforced move which leads to a pretty finale illustrating some tactical motifs. Crafty plays 3. ... f5 with +5.5 4. Rxe6 Qxe6 5. Nf6+ Kf8 (Qxf6, Qxc8 mates) 6. Bd6+ Qxd6 7. Qxc8+ ke7 8. Ng8#.


In the end, it was nice to find that Crafty agrees with my C2 variation with 3. Qf5 h6 instead of 3. Qg4, but the reason is that the iron monster forces a mate I didn't see.

Crafty: 4. Rxh6 gxh6 5. Nf6+ Kf8 6. Bd6+ Kg7 7. Nh5+ Kg8 8. Qf6 Qg4 9. Rxe8+ Kh7 10. Rh8#

Reinfeld position #422
Crafty's final word (after 6. Bd6+)

The Affluence Of Incohol

Blackburne, Pillsbury, Alekhine, Tal. They were all famous for it. Wild attacking Chess, that is.

I occassionally have a quick game on InstantChess.com when I have free games there, because it's "cup of coffee compatible". Erm, 'coffee', right. For some strange reason I play without inhibitions there.



The 5. ... b5 variation of the Two Knights Defense is always fun against someone who doesn't know the refutation 6. Bf1 and by 14. ... Rg8 I'd already dreamt the finale. 15. ... f5 (clearance) was the hard move to find and although Crafty prefers White at that point (it's evaluation drops from +2.6 to +1.6 with some analysis) after 16. exf5?? it's suddenly -11.5 and the little iron monster finds my move at depth 10.

The unfair thing about Chess is that 18. ... Qxf3 mating wasn't pretty enough for me - when you're playing a sac-sac-mate game, taking your opponent's pieces just isn't good enough! 18. ... Rxh2+ should lead to a draw by perpetual check, but here's the really silly thing...

Even when you're "Alekhined out of your mind" you'd think any normal person would notice they can execute the threat that's been looming since move 8, right? It was pretty much the whole point of the double Rook sacrifice, wasn't it? Apparently not so for me, I had to think "ooh look, he's giving me a free Knight!" and play 20. ... Bxe5+ then wait for White to finally lose on time.

Anyone got an aspirin?

Do You Know How To Analyse? Part 3

Trying to do this in the odd fifteen minutes here and there during breaks at work is probably not the best idea. I have half a page of 'analysis', most of which is scribbled out and the remainder of which isn't up to much.

Of necessity doing it this way requires backtracking over previous work, when the discipline we're trying to establish is to move in a straight line from static analysis to candidate moves to analysis of variations to the move to be played.

I'll need to pick some simpler positions (1 or 2 candidates with fairly straight variations) and set aside an hour or two at a time on the weekend when I can concentrate on the task, then practice on more complex positions when I have the basic technique (discipline and calculation). Meantime rehearsing tactics seems to be a more useful thing to do in odd little moments here and there.

Do You Know How To Analyse? Part 2

Kotov recommends we analyse the following position where Black's moves are largely forced before proceeding to read about the analysis of unforced variations, and so I began this task during my lunch break today.

Boleslavsky vs. Ravinsky, 1949 (variation)
Kotov position #9
Black to move

The question is "... what variations would arise after 20. ... Ke8 21. Nd6+ Kf8 22. Qf3+ Nf6 23. Re1?"

As my copy of 'Think Like A Grandmaster' is conveniently printed in two column format, I folded the page in half so as to hide the solution and spent twenty minutes or so looking at the diagram. This should be around the time required to complete the whole excercise - I got as far as 'clearly ennumerating the candidate moves'. Not too great a concern, I'll be happy to get the method and technique correct before working on speed... "It is better to do something once slowly and correctly than ten times quickly and wrong".

Static Assessment: Black is a Rook for a pawn ahead in material, in compensation for which White attacks Black's insecure King. There's an absolute pin on the Knight at f6 which is also attacked by a pawn. White has a discovered check by moving his Knight at d6. Difficult for Black to close lines to his King or hide it in the corner, while White potentially has a weak back rank.

Candidate Moves: In listing the candidate moves, I also decided to make a brief note about the underlying idea befind each.

A. 23. ... Bc5 - defending the discovered check.
B. 23. ... Qg4 - to exchange material, Black threatens to win by attrition.
C. 23. ... Bxe5 - to relieve pressure on the pinned Knight, clearance of the d-file aiming the major pieces at White's weak back rank.
D. 23. ... Kg8 - unpinning the Knight.

Here's the position from which the analysis really starts, although it should be done from the position given above.

After 23. Re1