Sunday 22 April 2012

Solution for a combination

Click to enlarge
So a question for this position was, is it better to misplace Black queen with 25.Rd2 or just to take an exchange with 25.Nd6 .

White to move!  
Bejtovic J. (2335)- Bednar M. (1988) Ceska Trebova 2008

As I said in a previous post, black put a hard resistant after very good opening preparation from me. This is somehow critical position in the game. I could play 25.Nd6 and White will indeed win a exchange but I somehow felt that after 25.Rd2 must be a combinational solution. It forced me to look deeper in the position and I found quite interesting ideas, but one detail was not in right place. As you will see from the text it is trivial detail but that is often reason behind all missed combinations.
So let´s do a some work.

25.Rd2 (As I said 25.Nd6 wins exchange for White, but Black has a pawn and some chances)
25...Qa3 (Only move. Black queen is far from real battlefield)
26. Qd4+, Kh6 (By far a safest square for Black king. Now, we have position from next diagram)

Bejtovic Czech Republic Chess
Position after 26...Kh6
Of course, calculating position before move 25, it is easy to get here but a real blow has to be found in this position or White has to play 25.Nd6 with some advantage. Maybe is possible to play 27.Nd6 now but somehow I felt that if I want to take exchange I have to take it immediately.
So what is a main problem in this position. It was very strange to me that White can not do something when Black´s queen and Black´s king  is far away from each other. White need to sacrifice more material, just to open lines and diagonals toward Black´s king. It was simple to see what to try.

27.f5 !! (This move not only opens c1-h6 diagonal but also f file which will be very useful. It is not only fxe6 which is treth but also f5-f6 just to cutt off Black´s king retreat to g7 and mate him with Qe3+ )
27...Bxf5 (27...gxf5 28.Qf6+, Kh5 29.Qg5 mate)
28.Nd6 (Only now this move, which main purpose is not to take one of Black´s rooks but to play Nf7+ or Nxf5+ with quick mate)
27...Rxe2 !? (Interesting try. Rook on c1 is hanging and White has to do something with checks)
Position after 27...Rxe2
When thinking about 25.Rd2 I saw this resource from Black.
I have to win with checks, was my thoughts. First idea is 28.Nxf5+ and Black has three candidate moves, which I analysed one after another.
Let´s do that by method from Alexandar Kotov. White has to list out all possible moves from Black.

a.) 28...Kh5
b.) 28...gxf5
c.) 28...Kg5

28.Nxf5+  and now I will examine all posibilities:

a.) 28...Kh5 29.Ng3+, Kg5 30.Nxe2 and White has a rook more (by defending a rook on c1)

b.) 28...gxf5 ( I had a big problems by calculating this move. I have a perpetual Qf6-Qf5 but it was hard to find more. I almost played 25.Nd6 concluding that there is no advantage for White here when I spot an idea which is very easy but not so obivious if you had a position on move 25 in front of you and had to analyse all the lines) 29.Qf6+, Kh5 30.Qxf5+, Kh6 ...and now comes move which I found very hard to see... 31.Qf4+! (X-ray defending rook on c1) and 32.Rxe2 with an easy win.

c.) 28...Kg5 This actually happened in the game 30.h4+, Kxf5 (30...gxh3 31.Qh4+, Kf5 32.Rf1+ wins, and 30...Kh5 31.Ng3+, Kh6 32.Sxe2 is not better. White also wins.)
31. Rf1+  and Black resigned without waiting for 31...Ke6 32.Txe2 mate


All this is very nice and I won a very nice game but this is not all which is important in this position. Black has more defensive resourcies which had to be analysed. We need to look a bit deeper in the position after White´s 28th move.
Position after 28.Nd6

Is there some other option to fight against Nf7+ and Nxf5+ (remember Black played 28...Rxe2!?).
Of course it is, and 28...Be6 parries both threats.
What should White do against that. First of all, we have to notice that 28...Be6 is defensive move and there are no threats to White position. Black can hardly find a good move and maybe White need to play something quiet. We need to put some fresh forces in the attack and also to remove Black´s only active posibility (Qxc1). Solution is natural 29.Rf1 .
Let´s do some analysies.

29. Rf1 (Black can not move his rook from e8 because of Qe3+ and Qxe6 and he has to try something active. His position is lost but I will give some variations witch illustrates that)
30. Qf4+, Kg7 31.Qf6+, Kh6 ( Of course not 31...Kg8 32.Nxe8,Rxe8 33. Rd8, Rxd8 34.Qxe6 and White is completely winning)
Position after 31...Kh6

It is not quite clear how White wins in this position but there is a fantastic blow. I have to admit that I didn´t found it during a game (as a meter of fact I didn´t calculated 28..Be6 at all ) but during my analyses I found it without of computer programs help. The key defender is Be6 and it has to be eliminated from e6 (than Nf5+ or Nf7+ wins). It can be done if both of White knights attacks one of these squares To accomplish that White has to sacrifice both rooks.

32. Rf5 !! and there is no good defence
32...cxd2 ( If 32...Bxf5 than 33.Nf7+, Kh5 34.Qg5 mate )
33. Rh5+ !, Kxh5
34. Ng3+, Kh6 ...and now both White knights attacks square f5 and White can mate on two different ways

35. Nf7+, Bxf7
36. Nf5 +, Kh5
37. Qh4 mate

another way is...

35. Ngf5+, Bxf5
36. Nf7+, Kh5
37. Qg5 mate

Coordination of White queen and knights is beautiful and this is one more example how dangerous can be combination  of queen and knight.

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