Saturday, December 30, 2006
"Which Tactic is This?" Revisited.
White to Move
2k1q3/p2r1p2/P7/Q6B/8/Kp2r3/8/6R1 w - - 0 1
Note: if you want to solve this checkmate problem first, better stop reading now!
.
..
...
..
.
I was stuck on this one for awhile and still did not get it right. The two easier variations are 1.Rc1+ Rc7?? and 1.Rc1+ Rc3. I won't comment on those - they are much more forced. I never could get through the 1.Rc1+ Kb8 variation completely on my own. After looking up the answer and working through it in subsequent circles, I began to appreciate this problem more.
Seeing that White's Queen could give check on b4 was alot different than giving check b5 was pretty easy. The key to the difficulty seems to be the c8 square. First it's where Black's King is, then Black is guarding c8 more times than it is attacked, then Black is guarding c8 once as it is being attacked once. At the same time the Black King is stuck in the corner, walking into a strange sort of back rank checkmate threat.
After 1.Rc1+ Kb8 2.Qb4+ Ka8 3.Bf3!+ Rxf3
I am now beginning to think I left something out of my Simultaneous Advantage post: tying down defenders. That is similar to immobilizing defenders, although they still have some movement available to them. Here is a simplified analysis of the above position.
Preexisting advantages:
- All of Black's King's flight squares have been removed.
- Black's Queen is tied down to the eighth rank to defend against the back rank checkmate threat Rc8#.
- Black's Rook on c7 is tied down to the seventh rank to defend against Qb7#.
On Qe4! Black gets some advantages from the move:
- Moving into capture - White's Queen is unprotected on e4
- Giving a King flight square - b8
White gets advantages which are terminal for Black:
- Forcing with check - this also implies "preventing counterattack" on White's King
- Threatening capture - Black's unprotected Queen is threatened with Qxe8+
- Removing King's flight square - a8
- Resulting checkmate threat - ...Kb8 Qxe8+ Rd8 Qxd8#
Defensive options:
Rook (on d7) to b7 walks into mate in one.
...Rb7 Qxb7#
Rook (on d7) to d5 walks into mate in two.
...Rd5 Qxe8+ Rd8 Qxd8#
Similarly Kb7 walks into mate in two.
...Kb7 Qxe8+ Rd8 Qxd8#
Queen takes Queen on e4 walks into the back rank mate in one.
...Qxe4 5. Rc8#
So what tactic (besides the fork aspect) is going on in the move Qe4? It seems to me as a special case of attacking the defender: a enprise attack on a tied down defender. Although Black's Queen is hanging, I believe a tied down defender essentially is equivalent to a hanging piece. Here's an example:
White to Move
Qb7! forks both Black Queens. Although they defend each other, the Black Queens cannot simultaneously defend against the back-rank mate threat and capture White's Queen.
-=-=-=-=-
I am getting a bit annoyed with this new blogger editor as it keeps adding lines, especially in bulleted sentences.**rolls eyes**. Perhaps WordPress is in my future...
Finished circle 4, and picking up some speed.
Happy New Year Everyone!
Circle 3 Complete
I have found two wrong answers, 513 and 524. The mating idea was right, it just took more moves.
Wednesday, December 27, 2006
Circle 2 Complete
Sunday, December 24, 2006
Circle 1 Complete
As I circle through my checkmate problems, I have begun to categorize the themes that come up in the checkmates that I often get wrong.
- Sacrifice not on the initial move
- Quiet moves, especially not on the initial move
- Opening lines to take away opponent's King flight squares
- Interference, forcing opponent's pieces onto his own King's flight squares, especially not on the initial move
- Overworked Defenders who are not overworked on or after the initial move
This leaves out taking extra moves to achieve mate, using squares beyond a1 through h8, or instantaneously promoting all of my pieces to Queens.
I am working on a universal definition of the weakest part of my chess game. So far I have two possibilities: either the part of my game that I am scrutinizing at this time or the more straightforward all parts of my game are very, very weak. This definition seems to apply to the majority of chess players, players at all rating levels as well. At least how they describe themselves ;-).
-=-=-=-=-
I wanted to put in a good word for GM Eugene Perelshteyn's French Defense opening lecture on chessfm. It was immensely accessible and well thought out. Although I never play either side of that opening, it didn't matter. I have not read his related books, but I gather they are quite good for beginner through intermediate level players.
These lectures are one of the biggest reason I joined the ICC - to support them to keep doing it =). I hope to see more.
Wednesday, December 20, 2006
Starting Circle 1
1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Bb5+ c6 6. Qe2 Qe7 7. Bd3 Nc5 8. Qxe7+ Bxe7 9. O-O Nxd3 10. cxd3 O-O 11. b3 Bf6 12. Nc3 Bf5 13. Ba3 Rd8 14. d4 Na6 15. Rfe1 b5 16. Bb2 Nb4 17. Rad1 Nd3 {White resigns} 0-1
Sunday, December 17, 2006
Circling Around Again
Although I still get in an occasional blitz game, it's only through blunders that I am in the 1300 range. I know playing lots of long games would help more, but in lieu of time considerations I am going to do a "holiday" 40 problem mini-circle out of medium difficulty checkmates from the book.
On a more upbeat note it is good to see so many interesting posts on other chess blogs including new Knights - I will add your links soon.
Thursday, December 07, 2006
Thinking in chess
Here is a parallel question. What is thinking in wrestling, like they have in the Olympics? Clearly the sport is a test of physical strength. All wrestlers are fit from training, so what determines the winner seems like a combination of things: strategy, tactics, timing, and space, especially if you consider that a wrestler can lose or gain by getting out of boundaries depending on the situation. The brain must be doing something for wrestlers.
Back to chess. I picked up an old chess book and casually reviewed some problems. I did not do much better on the "Combinations" section than I did before starting the TCT circles. I am busy and my chess is suffering. Anyway, I went back to the section on "Delivering Mate" and I quickly sailed through the easy mates. The tougher mates were a little slower. Surprisingly I didn't really recognize any of them. One just didn't make sense. I must have been too tired to calculate. Either that or lazy!
Problem 11, page 29
White to Move
This wasn't any pattern I recognized. I put the book down for five minutes, had my mind completely elsewhere, then picked up the book again and had the answer: Qe8. Because f8 was attacked twice by White, it seems logical for Black to take the Queen, but alas that is followed by a double-check. I had to laugh, as the d6 square was attacked no less than four times by Black!
I find it peculiar that the answer quietly popped out of nowhere. It was not visual, either. It sort of seemed mechanical, like pieces moving, as if to indicate, "do this". That is the mysterious chess thinking I have no clue about. And I can't imagine anyone becoming a strong player without it in one form or another.
