Suresh M. Mody S.M.Mody continues his series about Chess Problems started in the Nov 2003 Bulletin
H-6, Saraswati Society, NG Acharya Marg, Chembur, Mumbai 400 071
Email: sureshmody@vsnl.net
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Suresh M. Mody S.M.Mody continues his series about Chess Problems started in the Nov 2003 Bulletin |
Let us first see the solution to Problem No. 9 from the last issue.
The problem shows star-flights of both the kings. The tries as well as the key move are king moves leading to discovered checks. In problem parlance the king moves fire the R+K battery.
Tries:
| 1.Kf4+? Kd7! | 1.Kf2+? Kf5! |
| 1.Kd4? Kf7! | 1.Kd2? Kxd5! |
Key: 1.Kd3+
Variations:
| 1...Kd7 2.Pc8=Q# | 1...Kf5 2.Pg4# |
| 1...Kf7 2.Pxf8=Q# | 1...Kxd5 2.Ba3# |
While the white king fires the battery to check the black king, one or the other white pawn gets self-pinned. This weakness allows the black king a valid defence. For instance in the first try with the king moving to f4, the c7 pawn gets self-pinned and it cannot move to c8 to queen.
Pxb8=Q is not a check and Pxb8=N+ is met by Kc7 or Kd8. Similarly in the other three tries the pawns on g2, g7 and c2 get self-pinned. Even in the key, the c2 pawn gets self-pinned but white has another way to mate, which was not available with the king on d2. 2.Ba3 is not a mate after 1.Kd2? as black king has an escape to d4, not available after 1.Kd3!
Normally a checking key move is not considered as a good key. However in this problem the checking key is related to the theme and hence acceptable. The tries show the star-flight moves of the white king defeated by star-flight moves of the black king! The actual play also shows star-flights of the black king. A common weakness of self-pinning of a pawn provides a defence to black in the four tries. An excellent problem fully deserving the first prize it won.
In the last article we have seen problems where the theme concerned flight squares available to the black king. In this issue we will see a theme where one or more black pieces block the king's flight square(s). As we have seen earlier this is known as self-block. In some earlier problems we had seen variations that involved self-block; but it was not the central theme in such problems. In problem 10, it is the central theme. Six black men cause self-block on six different squares. As a pawn and a knight self-block on two squares each and two men self-block on c6 and d4, we get eight thematic variations. This is probably a task record - it certainly was when my source reprinted it.
Key: 1.Rc8
Threat: None. Waiting move
Variations:
| 1...Pxc6 2.Rd8 | 1...Nxc6 2.Nc7 |
| 1...Nd4 2.Nf4 | 1...Rd4 2.Nc3 |
| 1...Nc5 2.Nxb4 | 1...Pd6 2.Pe6 |
| 1...Pe6 2.Qe4 | 1...Pxe5 2.Qxd7 |
Blocking of the squares in the king's field by black's own pieces make the mates possible. Black king would have got an escape square if the squares were not blocked by one of its own men.
As is customary, we have mentioned only the thematic variations in the solution. I am sure the readers would have seen the mates after other black defences. Any other move of N(b4) opens up the line of the bishop on a3 for its control of d6 permitting 2.e6#. Any other move of N(b3) results in 2.Ra5#, any other move of R permits 2.Be4# and 1...Pc3 is met by 2.Bxb3.
Now let us see another problem with two thematic variations showing self-block and having other interesting features. In the set position, if white could just remove his knight from the board, there would be mate on the move. However the rules of chess do not permit that. We have to find a square for the knight to go so that the B+N battery can be fired to mate the black king. The available moves Ne6 and Nf5 interfere with the control of one of the white rooks on e-file and 5th rank respectively.
Key: 1.Re7
Threat: 2.Ne8
Variations:
| 1...Re3 2.Ne6 | 1...Rc5 2.Nf5 |
| 1...Rf3 2.Re4 | 1...Rc6 2.Rd5 |
| 1...Rg3 2.Re4 |
The first two variations are thematic. The self-blocks relieve the white rooks of their responsibility of guarding e3 or c5 and hence in spite of the blocking of their path by the knight it is mate. We have not considered 1...Rc8+ as it does not defeat the threat.
Another interesting fact is an echo effect in the variations. If we consider the long diagonal a1-h8 as an axis of symmetry variations 1 and 2 as well as 3 and 4 are mirror images. Such mates are called echo mates.
We leave you with an interesting problem to solve. It too shows self-blocks in thematic variations and has another theme that we have seen earlier in this series.
Solutions to the problem of Diagram12 and comments about the article should be sent directly to the author at the address/email address given at the beginning of the article. sureshmody@vsnl.net
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