Where the idea's connect
We know the basic elements well. Confusion arises where the different ideas connect. This is what we need to learn. The logic to connect basic ideas.
 |
| White to move |
3r2k1/p3pp1p/1p4pB/4q3/2n1Q3/7P/PPR2PP1/6K1 w - - 0 23
#21. Keres, P. vs. Tal, M., Parnu 1971 (Analysis)
White has the following choice:
- give a check (which is impossible)
- prevent blacks counter attack 23. ... Rd1#
This prunes all alternatives for white beforehand.
The funny thing is, that black's rook is factually overloaded:
- it must prevent the back rank (invasion Qa8 threatens)
- it must attack d1, thus limiting the possibilities for white
White must prevent Rd1#, and try to distract the black rook with one move:
- 23.Rd2!
Black cannot take the white rook with his knight since it has the duty to defend the black queen.
The black queen cannot take the white queen because white threatens mate in 1 with Rxd8#.
The black rook cannot take on d2 since it has to protect the back rank.
This position gives a good idea what there is to learn from such positions. It took me two days to get rid of the confusion. (I typically study 3 hours per day).
Seeing all basic ideas in the position is not the difficulty. But constructing a line of reasoning is the hard part. And pruning is at the core of the logic.
The Trick gives you speed and visualisation for free. Where does that come from?
ReplyDeleteThe Trick is deeply based on understanding.
It took me 6 hours to get to the essence of the logic. Now I can do it in a few minutes. That is 180 times faster. That is where the speed comes from.
The logic is accompanied by SEEing the logic. That is where the visualization comes from.
During the process, I got rid of some biases. By an overloaded piece I think of a rook with two defensive tasks. Here we have a black rook which has one defensive and one offensive task.
Fiddling around, I discovered that the coverage of d2 by Bh6 is essential. Otherwise blacks Qe1+ would have been an issue.
I “SEE” it somewhat differently. Quel surprise.
ReplyDeleteThe order of threats is just as important as the forcing level [CMCT] of those threats.
Start with the relative safety of the two kings. Because of the WBh6, Black’s king is constrained to the back rank with a serious back rank mate threat [CMCT] against it: WQa8. The BRd8 is chained to defending the back rank UNLESS (1) it can create an Equal or Greater Threat (EGT) against the White king (which it does) AND (2) Black can get the move (initiative). Black CANNOT get the initiative UNLESS White gives it up by playing a non-forcing move.
The White king also has a serious back rank mate threat against it from a combination of two pieces: BRd8 threatens mate on d1 BECAUSE the BQe5 creates the back rank mate conditions (king constrained to the back rank); although the WQe4 could interpose, that would merely delay the inevitable. The BQe5 does not threaten mate on its own on the e1-square because in so doing, it would allow the WKg1 to move to h2.
White, having identified the Black back rank weakness, should ATTACK THE MOST SIGNIFICANT WEAKNESS. That can only be done by attacking the BRd8 (constrained defender) while maintaining the back rank mate conditions (WBh6 + WQa8 mate threat). Ergo, WRd2 directly attacks the weakness.
The “cleanup” is to determine: What can Black do (if anything) to prevent the back rank mate?
It would appear that Black has a defense by capturing BNc4xd2. WAIT! The BNc4 has the function of protecting BQe5. 1. Rd2 Nxd2 2. Qxe5 and White threatens mate again on g7. The back rank threat against White is gone and Black is material down. So, the BNc4 is constrained by its function of the defense of BQe5; no can do.
It has already been determined that the BRd8 is constrained to limited movement ONLY along the back rank. After 1. Rd2 Rc8 (supposedly to “protect” the BNc4 and the back rank—two functions = WEAKNESS) 2. Qxc4 and the BRc8 cannot recapture on c4 because the WRd2 now threatens back rank mate. Black could respond with 2.… Qe1+ and capture the WRd2—except for the nasty facts: (1) the vis-a-vis between WQc4 and BRc8 means that the White queen now creates a back rank mate threat, and (2) even if that were insufficient, the WBh6 protects the WRd2. However, it would be stupid for White to play 1. Rd2 Rc8 2. Qxc4 Qe1+ 3. Kh2 Qxd2 4. Bxd2?? Rxc4.
What is the takeaway? The CMCT hierarchy of threats implies a consideration of application order. Constraints (functions) are also very important considerations. It is necessary but insufficient to consider only positive threats; negative (preventative) threats must also be factored into the logical sequence.
FEN: 4Qr1k/pp4pp/2p5/8/3p3q/3P4/PPP2PPP/4R1K1 b - - 0 1
ReplyDeleteWhy Grandmasters See Moves You Can't See
https://www.youtube.com/watch?v=Z6WlxDHcGPY
CM Azel Chua’s example in this short video is an excellent illustration of “SEEing” negative threats (although he does NOT use that terminology).
Based on known patterns, it seems “obvious” that Black should play 1.… Qxf2+ (highest forcing level), with a back rank mate as the possible followup.
CM Chua’s first comment is “This position is a lot trickier than it looks.” After 1…. Qxf2+ 2. Kh1 it almost “feels” (System 1’s pattern recognition) that there is either a standard back rank mate. However, 2.… Qf1+ would be a disastrous continuation: 3. Rxf1 and Black CANNOT recapture on f1 with 3.… Rxf1# because the BRf8 is absolutely pinned.
So look for something else. The BRf8 is absolutely pinned by the WQe8, so capture the queen should be the next consideration. 1.… Qxf2+ 2. Kh1 Rxe8 (since the rook and queen move along ranks and files, either piece type can “break” a pin by moving along the line of attack from pinned piece to pinning piece, capturing the attacker). BUT, it turns out that Black also has a back rank problem: 1.… Qxf2+ 2. Kh1 Rxe8 3. Rxe8+ Qf8 4. Rxf8#.
It appears that Black is stymied.
What is the problem? If Black (somehow) could get rid of the effect of the absolute pin, then he would have two threats at once and White would not be able to defend both of them. There is NO solution involving the back rank mate on the f1-square. Changing focus to the BRf8 vis-a-vis WQe8, the reason the Black rook CANNOT capture the WQe8 is the consequences of capturing the queen, FOLLOWED BY White having a mating sequence on the back rank.
The question is: how can Black NEGATE the absolute pin on BRf8?
Capturing WQe8 is not possible—but it is not the only way to neutralize an absolute pin. Interposing another piece between BKh8 and WQe8 is one possibility (not available in this specific position). How about opening up an “escape hatch” by creating luft? 1…. Qxf2+ 2. Kh1 h6 creates luft. What is harder to “SEE” is that the absolute pin has been broken. Now Black can capture the WQe8 without a back rank mate followup.
White has to move his queen away from the Black back rank. He also has to protect against the stock back rank mating pattern. Unfortunately, there is no safe square from which to perform both functions. 1…. Qxf2+ 2. Kh1 h6 3. Qe2 fails to 3.… Qxe2 4. Rxe2 Rf1#.
We often get “hung up” trying to choose between two attacking alternatives [the Buridan’s Ass problem], trying to figure out how to get the available pieces rearranged into a winning configuration. Sometimes the answer can be found in the middle of the logical sequence with a move that NEGATES a threat.
"If it feels like you're choosing between the lesser of two evils, DON'T. There is always a HIGHER choice."
Author: Michael Neill
That “higher choice” may be found in a negative direction.
That is where two isolated ideas connect.
Delete