PROBLEM SECTION 12

A random move of the white bishop on d4 leads to a threat of 2.Qd4. If the random move is on the a7-g1 diagonal, there is an additional threat of 2.Qf5. The threat(s) are defeated by 1...Pxf1(=Q or R). A specific move of the bishop to f2 is the White correction and it becomes the key. The other try is non-thematic.

The placement of the white king on b7 is very apt as it prevents a cook 1.Rf3 Pe1(=any) 2.Bb7.

The problem has very few variations and little by way of virtual play too. However showing, in a miniature setting, a theme that usually requires much heavier setting, is commendable

The problem is rich in virtual play. A random move of the key piece – the knight on e6 – removes its control on f4 permitting a cross checking defence against which a set mate was provided. Three more specific moves of the key piece lead to different errors leading to a successful defence. This leads to three more tries and a wide variety in the virtual play.

Set:	1...Pf3+ 2.Bf4
Tries:	1.N(e6) at random? (for 2.Qe7) Pf3+! 1.Ng7? Bd6! (1...Pf3+ 2.Ng4) 1.Nd4? Pxc3! 1.Nc5? Nc8! (1…Pf3+ 2.Rxe4)
Key:	1.Ng5
Threat:	2.Qe7
Variations:	1…Pf3+ 2.Rxe4 1…Bd6 2.Qh8 1…Nc8 2.Pxc6 1…Pxc3 2.Bxc3

In the last section, we had seen the four phases in the Black Correction theme:

1. A general defence
2. A general error One or more secondary defences
3. One or more secondary errors

In this case the general attack is the random move of the knight on e6 threatening mate by 2.Qe7. The general error is the removal of the control the knight had on f4. The result is the loss of the available set mate 2.Bf4 after 1…Pf3+. While defeating the key, 1…Pf3+ blocks the line of the black bishop on d1 and the queen. Three specific moves of the knight take advantage of this to provide mates after 1…Pf3+. Thus these tries take care of the general error but introduce new errors giving rise to new defences. For instance 1.Nd4 blocks the possibility of a check by the bishop against 1…Pxc3. Similarly 1.Ng7 blocks the possible line of check by the Queen from h8 and 1.Nc5 blocks the path of the rook. The key move takes of the general error as well as the three secondary errors.

The arrangement set in the position, particularly the half-battery gives a clue to white’s line of attack. The key has to be the move of one of the rooks threatening mate with the move of the other rook. However the question is which rook should move first and where. These options give rise to as many as nine tries and the key!

Tries:	1.R(f5) at random? Qd6! 1.R(f5)f4? PXh3 1.R(f5)e5? Ra6! 1.Rd5? Be8! 1.Rf6? PXf6! 1.R(e4) at random? Qd6! 1.R(e4)f4? Pf2! 1.R(e4)e5? Rd7!
Key:	1.Rd4
Threat:	2.R(f5) any
Variations:	1…Qd6 2.Rf6 1…Pxh3 2.Rg5 1…Ra6 2.Rf6 1…Be8 2.Rf7 1…Pe5 2.Rxe5

A random move of either rook threatens mate on any move of the other rook. Black has a defence that parries the threat – 1…,Qd6. From d6 the queen can capture the queen or interpose on d3. White can either block the path of the queen to d6 by playing either rook to f4 or e5 or block one of the two lines, d6 to g6 or d6 to d3 to provide mates against 1…,Qd6. Such moves – and there are as many as eight of them - can make the defence 1…,Qd6 ineffective. All these correct the error of random moves. However seven of these create new errors giving rise to new defences. For instance after 1.fRf4 the key piece interferes with the move of the other rook to g4 allowing 1…,PXh3! Similarly 1.eRf4 results in blocking the line of the f rook from f5 to f3 making 1…,Pf2 an effective defence. Four tries arise due to mutual interference between two similar pieces on f4 and e5. Moving a rook to d5 or e6 interferes with the bishop’s control over b3 permitting 1…,Be8! or 1…,Bb5!. 1.Rd4 is a correction that does not introduce a new error and is the key.

This excellent composition is very rich in both virtual and actual play.

Like problem no. 4 in the last section, this one also shows tertiary correction or continuous correction or corrected correction.

Tries:	1.N at random? (for 2.Qe5) Qb8! 1.Nc4? Re1! (1…Qb8 2.Ra5) 1.Nd7? Bg7! (1…Qb8 2.Rc5)
Key:	1.Nb6
Threat:	2.Qe5
Variations:	1…Qb8 2.Qxd4 1…Re1 2.Nxb4 1…Bg7 2.Nxe7 1…Kc5 2.Qxd4

A random move of the knight is met with 1…,Qb8. Two tries correct the error and provide mates after 1…,Qb8, but introduce new errors. 1.Nc4 blocks the bishop’s possible check from b3 thus releasing the rook from guarding the b file and stopping the threat by 1…,Re1. Similarly 1.Nd7 blocks the possible check by the queen from d8 making the defence 1…,Bg7 effective. The excellent key allows the black king a flight square by blocking the control of the rook on c5. New mates are provided for the three defences as well as for the king move. No wonder the problem received a first prize.