Pandolfini's Puzzler #36 - April Fool's Day: Queen vs. Pawn

Pandolfini's Puzzler #36 - April Fool's Day: Queen vs. Pawn

brucepandolfini
NM brucepandolfini
Apr 4, 2014, 12:00 AM |
22 | Scholastics

Professor: Hello, Class. Happy April Fool’s Day!

Lucian: Professor, April Fool’s Day has come and gone. It was three days ago.

Zephyr: I prefer to think of April 1 as being Rachmaninoff’s birthday.

rachmaninoff.jpg


Lucian: I don’t know if I’d play chess on April Fool’s Day.

Zephyr: I would if it were my birthday.

Professor: Enough interplay. How about we get down to some real chess?

Lucian: Sure, Professor. What did you have in mind?

Professor: I was thinking about examining positions in which a lone queen must contend with a far-advanced enemy pawn, say on the 7th rank, about to queen, supported by its king.

Zephyr: Are you talking about situations where the side with the queen can’t expect immediate help from its own king?

Professor: Yes, those are the situations I had in mind. I’d like to know how the queen fares against the king and pawn. I’d also like to know if it matters what type of pawn is involved.

Queen vs Pawn2.jpg

Lucian: What do you mean by “type of pawn?”

Professor: For this discussion, there are four types of pawns: center pawns, bishop-pawns, knight-pawns, and rook-pawns.

Lucian: I see what you’re getting at. Different kinds of pawns can pose different problems and have their own features.

Professor: Correct. Now before we actually look at the peculiarities of the different kinds of pawns, can either of you explain the general winning technique for the side with the queen?

Zephyr: It would be my pleasure. Using checks, pins, and threats, the queen improves its position so that the enemy king is driven in front of its pawn, blocking the pawn’s immediate advance for the next move. Then, with the pawn blocked, the friendly king can use the tempo to get a square closer. Eventually, after the process is repeated a few times, the friendly king gets close enough to the target area to help win the pawn and/or force a quick mate. That’s the essential approach.

Professor: Very well put. Perhaps you should be giving your own chess class.

Lucian: I think she’s getting there, Professor. Maybe one day she’ll be ready to take over this class. Perhaps I’ll be able to do that, too. By the way, Zephyr, when you use the expression “friendly king,” what do you mean by it?

king dreaming white.png

Zephyr: By “friendly king,” young man, I suppose I mean the king whose side represents the analyst’s point of view. That is, I like to think of it as being friendly to me and my analysis.

Lucian: I guess that means, if I’m sitting at the other side of the board from your perspective, my king is the “enemy king” and I’m the enemy.

Zephyr: Yeah, something like that.

Professor: All jibes aside, direct or indirect, jocose or not, let’s take a look at the first position.

Question 1: Can you show a sample winning variation for White against the center pawn?

At this time, the two brainy children quickly came up with an example of the winning procedure. The Professor was delighted.

Professor: That’s very good. The method the two of you have just shown me does display the right way to go about doing it – that is, when the queen is facing off against a center pawn.

Zephyr: Actually, Professor, the same technique also works against a knight-pawn.

Lucian: In fact, against a knight-pawn, the win tends to come about a little more easily and faster. That’s because the edge of the chessboard reduces the operating space for the defending king. The result is the king winds up blocking the pawn a step or two sooner.

Professor: I’m impressed with the both of you - your knowledge, and how nicely you articulate concepts. Without overdoing the bombast, can you suggest how White should proceed in the following diagram?

Question 2: Can you show a sample winning variation for White against the knight-pawn?

Very quickly, the two astute problem solvers analyzed a compelling winning line. Once again, they were ready for more.

Professor: OK. You’ve explained how the side with the queen can win against a center pawn and now against a knight-pawn. What’s the story for the bishop-pawn? Does the queen win or not?

Zephyr: Well it depends on several factors. A key question concerns whether the defending king can reach the corner. If it can, it’s usually a draw, unless the friendly king is nearby. Sometimes, however, the defending king is cut off from the corner by the queen, and that could change the result, especially if the attacking king (the friendly one) is close enough to participate.


Question 3: What is White’s best move?

Lucian: Now that’s an easy problem.

Zephyr: No, Lucian, it’s even easier than that.

Both gifted pupils were right. Each one was able to show why diagram 3 ends in a draw and did so simultaneously, one speaking over the other.

Professor: Your garbled chorus of explanation works for me. But what happens if the defending king can’t reach the corner?

Zephyr: True, sometimes the queen cuts the defending king off, and if the attacking king is also close, the ensuing mate can be sudden and cruel.

Lucian: I don’t want to add poetry to the musical mix, but didn’t T.S. Eliot refer to April as the cruelest month?

eliot.jpeg

Zephyr: I didn’t know you’ve read the Wasteland.

Lucian: Are you kidding me? I love the way Eliot talks about chess in the second section as much as I love Rachmaninoff’s second piano concerto or second symphony.

Professor: Kids, without referring to music, poetry, or the cruelty of April, how would the two of you like to see our next problem?

Zephyr: We’d love that, Professor.

Lucian: Yeah, we’d love that, too.

Professor: OK, time to solve the next problem. Let’s say the onus is on us.



Question 4: How can White force mate in 2 moves?

Zephyr: This problem is not really that tricky, Professor.

Professor: Tricky or not, do you recall how to analyze a position like this one?

Lucian: You mean a position where the defender has very few moves?

The Professor smiled, and both Zephyr and Lucian understood. Within a minute or so, they had worked out the answer.

Professor: That was nice. But you know we’ve left out one kind of pawn: the rook-pawn.

Zephyr: We already know the scene with the rook-pawn by implication. It’s going to be a draw.

Lucian: Zephyr makes implications. I merely draw inferences.



Professor: Regardless who’s implicative and who’s inferential, how about turning the logical lens on the next problem? It really is a basic position.


Question 5: Can Black win by force?

To be sure, the smart kids quickly dispatched the problem, which they viewed as nothing more than a defining illustration.

Zephyr: Professor, we were hoping you had a slightly more interesting problem than that. Do you have another example that features the rook-pawn yet tests us a tad?

Professor: You tell me. Does this next problem seem more challenging?

Professor: Allow me to set the stage. The position actually occurred in a six-board blindfold simultaneous I gave many years ago.

Zephyr: You once gave a blindfold simultaneous?

Lucian: Are you sure? You seem so old and professorial. You might be mistaken.

Professor: Yes, it’s true. I am old and somewhat professorial, and often mistaken, but I also used to give exhibitions. The following position arose in one of them. Leading up to this position, I had won the pawn race. Probably my opponent thought the position was drawn anyway. But he hadn’t considered something, which upset the applecart.

cart.jpeg

Question 6: Can White to move force a win?

This problem proved to be a lot more difficult than the kids anticipated. The two wondrous ones needed all of six minutes. But they found the unexpected resource nonetheless, thanks to Black’s extra pawn, which served as a kind of Achilles' Heel.

Professor: Once again, I am impressed and most pleased.

Lucian: Thank you, Professor, though I still have doubts about you giving an exhibition of any kind, let alone a six-board blindfold simul.

Zephyr: Hey, Lucian, let’s give the Professor a break. Besides, we want to keep him in good humor so that he shows us another problem.

Lucian: Very well, Zephyr. Do you have another problem, Professor?

Professor: Indeed, I do. Let’s check it out now.



Professor: Here’s the situation. Black has a rook-pawn, but the white king is ostensibly far away. So Black’s hoping to be stalemated before the white king can get close enough to join the attack.

Zephyr: Although it could take a while, I’m getting a sense there might be all kinds of ploys to wend the white king closer in a timely way.

Lucian: It does take a number of moves, but I can see a few time-gaining tries myself.

Professor: Terrific! Now answer the question, showing how the king can traverse down the board with dispatch.

Question 7: Can White force a win?

Another hard one, but not for the dynamic duo. In eight minutes it was all done, side variations worked out and jokes included.

Professor: What a great class this is! Because you’re so wonderful, I think I’m going to leave you one more problem. But I’m getting tired of the queen. I think for this example I’d rather replace it with a rook. Heck, I have to have some fun, too.

Zephyr and Lucian: Oh, Professor, can you just show us the problem?

Professor: Why not? Besides, I’m getting hungry and it’s time for lunch.



Question 8: Can Black move and draw?

Zephyr: Despite promoting with check, Black doesn’t escape the inevitable. I think I have the answer.

Lucian: I also think I have the answer.

Professor: Fantastic! Maybe now I can have my lunch.



Answer below - Try to solve ProfessorPando's Puzzle first!

ANSWER #36

For problem 1, Zephyr gave the following sample winning variation: 1. Qd3 (getting on top of the pawn, an expression the Professor likes to use) 1…Kc1 2. Qc3+ (forcing the black king to block the pawn) Kd1 3. Kb4 Ke2 4. Qc2 (pinning the pawn) Ke1 5. Qe4+ Kf2 6. Qd3 (getting on top of the pawn) Ke1 7. Qe3+ (forcing the black king to block the pawn) Ke1 8. Kc3 Kc1 9. Qxd2+ Kb1 10. Qxb2 mate.



For problem 2, the wonder kids offered the following sample variation: 1. Qa4+ (forcing the king to block the pawn) Kb1 2. Kb4, and after 2…Kc1, among the several paths to victory, they chose 3. Kc3 b1/Q 4. Qf4+ Kd1 5. Qd2 mate.



For problem 3, White to play doesn’t have to block up the pawn with 1. Kc8. Instead a draw is arrived at by 1. Ka8!, since 1…Qxc7 is stalemate.



For problem 4, White mates by 1. Qb4!. That prevents 1…Kd2, instead forcing 1…Kd1, which is resolved by 2. Qe1 mate!



(A way to solve a problem like this one would be to begin the analysis, not by looking for White’s move, but by looking for Black’s move, commencing a kind of retrogressive analysis. Now Black to play has but two initial moves, either Kc1-d1 or Kc1-d2. Let’s say White mulls Kc1-d1. White could then mentally ask: Where would I like my queen to wind up once Black’s king is on d1? The answer obviously is e1, which would be mate. With further consideration, by factoring in the need to also guard d2, while maintaining the cutoff on the b-file, it’s not hard to come up with the right first move, Qb3-b4.)

For problem 5, the position is clearly drawn after 1. Ka8, since Black is unable to take advantage of the pawn’s blocked state. Bringing the black king closer results in stalemate. So no progress is possible.




For problem 6, White began his winning line with 1. Qb4+. After 1…Kc2 (threatening to promote), White continued 2. Qa3 (getting on top of the pawn). There followed 2…Kb1 3. Qb3+ Ka1. Possibly Black thought the position was heading toward stalemate after White (the Professor) grabs the h-pawn. But White didn’t grab the h-pawn. He left it on the board and played 4. Qc2!. Now Black still has a move: he could play 4…h2, and that allows 5. Qc1 mate! It was another case of more being less.



For problem 7, White begins by playing 1. Kb6!. This gets the king a square closer and keeps the queen screened along the b-file, avoiding stalemate. Let’s say Black now plays 1…Kb1 (or 1..Kb2, it doesn’t really matter). White can then use a discovered check to move the king closer, say 2. Ka5+ (or 2. Kc5+, which works just as well).

If Black then plays 2…Kc2, threatening to promote, White has the powerful queen centralization, 3. Qe5!.That essentially forces 3…Kb1 (otherwise White plays 4. Qa1, and that’s all folks).

Play could then continue 4. Qe1+ Kb2 (if 4…Kc2, then 5. Qa1 stops the pawn for good) 5. Qd2+ (inching closer) 5…Kb1 (threatening to promote), and now 6. Ka4 (or 6. Kb4, but 6. Ka4 rubs it in more) 6…a1/Q+ 7. Kb3, and Black is lost. There’s a last-hope, fanciful try, 7…Qc3+, but it’s refuted by 8. Kxc3 (of course, not 8. Qxc3??, since that’s stalemate).



For problem 8, the answer to the question is NO. Black to move can’t save the position.

Assuming Black plays 1…a1/Q+ (underpromoting to a knight, 1…a1/N, doesn’t help because of 2. Rh1+, winning the knight), White merely continues with 2. Kb3, and Black is helpless against the mate threat at h1, even though Black has the move and a queen for a rook.




Take note

The above problems are not difficult, but they are important, and veteran players need to understand the circumstances leading to a draw or win.

One way these situations arise is by pawn races, where each side tries to queen first. Sometimes the resulting races end in both sides queening, with a plain old draw in sight. In other cases, both sides get to promote and one of the players has a tactical trick, winning the other player’s queen (such as in the final scene of Searching for Bobby Fischer).

In other instances, only one player gets to queen. That player then tries to stop the opponent from promoting altogether, even when the enemy pawn is on the seventh rank. Cut through all the interchange, and that’s what this week’s column is mainly about. 


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