## Saturday, January 12, 2013

### TGIF brain challenge

I am giving you a hard one for Friday night fun. White to move and win! No computer please!

Hint: Some lines go as long as 10+ moves.

Ralph said...

My first thought is that given the restrained position of the black king, this would be almost trivial without the pawn on c4:

1. Qc3+ Kg8 2. Qc8+ Nd8 3. Qxd8+ Kf7 4. Ng5+ and wins the Queen.

Then, once you realize that the black king is in tight quarters and black can only interpose the queen on g8 when the king is on h8, it just takes some geometric working around the pawn. Obviously, the long diagonal, allowing checks on h1, a8 and a1 will be key:

1. Qc3+ Kg8 2. Qg3+ Kh8 3. Qb8+ Qg8 4. Qh2+ Qh7 5. Qb2+ Kg8 6. Qg2+ Kh8 7. Qa8+ Qg8 8. Qh1+ Qh7 9. Qa1+ Kg8 10. Qa8+ Nd8 11. Qxd8+ Kf7 12. Ng5+

James I. Hymas said...

7k/5n1q/4N3/1K6/2p5/4Q3/8/8 w - - 0 1

Objective is to check along the eighth rank when the Black King is on g8.

1.Qc3+ Kg8
2.Qg3+ Kh8
3.Qb8+ Qg8
4.Qh2+ Qh7
5.Qb2+ Kg8
6.Qg2+ Kh8
7.Qa8+ Qg8
8.Qh1+ Qh7
9.Qa1+ Kg8
10.Qa8+ Nd8
11.Qxd8+ Kf7
12.Ng5+ Kg7
13.Qe7+ Kg6
14.Nxh7

Yancey Ward said...

If white could drive the king to g8 by checking along the a1/h8 diagonal, and then check from the 8th rank, he could win black's knight (and I can even see that after blocking at d8 followed by the capture with check, white will also win the black queen after a knight fork). However, white can't do this immediately. In any case, this leads me immediately to 1.Qc3+ and hope I can maneuver the position I have in mind. Let's see where this might take us:

1. Qc3 Kg8

Of course, Qg7 is mate in 1 more white move. After Ne5, white captures, then checks from b8 and then plays Ng5 forking the king and queen to win (similar to what I have in mind for the end of this line). So, if the black didn't have the c-pawn, white would check from c8 to win the knight and queen like above. So, can white maneuver to check from either d4 or a1 allowing a followup check on the back rank with the king at g8? All there is from 1. ...Kg8 is Qg3:

2. Qg3 Kh8 (Ng5 3.Qb8! Kf7 4.Ng5)

Now, white can check from the back rank, but the black king is on the wrong square at the moment. However, Qb8 is the only safe check available, so we must continue:

3. Qb8 Qg8

I think it is mate after Nd8: [3. ...Nd8 4.Qd8 Qg8 5.Qh4! Qh7 6.Qf6! with either Qf8# or Qg7# on the next move]. So, now, white's only safe check is from h2:

4. Qh2 Qh7 (Nh6 5.Qh6 Qh7 6.Qf6+-)
5. Qb2 Kg8

So, white has now returned to a position we saw after move 1, but with the white queen on b2 instead of c3, however, he still can't check from the back rank. So, we again go through another iteration, but with the check from g2 instead of g3 as we saw at move 2. Let's follow the bread crumbs, though I see it clear to the end in my head now that I have gotten within 4 moves:

6. Qg2 Kh8 (again Ng5 leads to #)
7. Qa8 Qg8 (again Nd8 loses)
8. Qh1 Qh7 (again Nh6 loses)
9. Qa1 Kg8
10.Qa8

The position I had in mind at the beginning is now reached, and black has only 1 move. Continuing:

10. ....Nd8
11.Qd8 Kf7
12.Ng5 and it is over.

Ein Steppenwolf said...

1. Qc3+
|
+- 1. … Ne5
| 2. Qxe5+ Kg8
| 3. Qb8+ Kf7
| 4. Ng5+ and
| 5. Nxh7
|
+- 1. … Kg8
2. Qg3+
|
+- 2. … Ng5
| 3. Qb8+ Kf7
| 4. Nxg5+ and
| 5. Nxh7
|
+- 2. … Kh8
3. Qb8+
|
+- 3. … Nd8
| 4. Qxd8+ Qg8
| 5. Qh4+ Qh7
| 6. Qd4+ Kg8
| 7. Qd8+ Kf7
| 8. Ng5+ and
| 7. Nxh7
|
+- 3. … Qg8
4. Qh2+
|
+- 4. … Nh6
| 5. Qxh6+ Qh7
| 6. Qf6+ Kg8
| 7. Qf8#
|
+- 4. … Qh7
5. Qb2+
|
+- 5. … Ne5
| 6. Qxe5+ Kg8
| 7. Qb8+ Kf7
| 8. Ng5+ anad
| 9. Nxh7
|
+- 5. … Kg8
6. Qg2+
|
+- 6. … Ng5
| 7. Qa8+ Kf7
| 8. Nxg5+ and
| 9. Nxh7
|
+- 6. … Kh8
7. Qa8+
|
+- 7. … Nd8
| 8. Qxd8+ Qg8
| 9. Qh4+ Qh7
| 10. Qd4+ Kg8
| 11. Qd8+ Kf7
| 12. Ng5+ and
| 12. Nxh7
|
+- 7. … Qg8
8. Qh1+
|
+ 8. … Nh6
| 9. Qxh6+ Qh7
| 10. Qf6+ Kg8
| 11. Qf8#
|
+ 8. … Qh7
9. Qa1+ Kg8
10. Qa8+ Nd8
11. Qxd8+ Kf7
12. Ng5+ and
13. Nxh7

Anonymous said...

Qd4 Kg8
Qg1 Kh8
Qa1 Kg8
Qa8 fat lady time

Yancey Ward said...

pht,

I left you a reply on the "Devious Chess Tactic" problem from 1/10/2013.

davey said...

Qd4-g1-a1-a8 etc

Craig Johannsen said...

RE: Qd4-g1-a1-a8 approach, black can bust it up by playing 2... Ng5, losing the knight but preventing imminent mate.