Wednesday, July 8, 2009

Mate Analysis from Yusupov's BUYC2

Just to give a taste of the level of Yusupov's book, here are the first 6 positions from Chapter 1, with my own, often flawed, analysis. It seems that I am capable of both relatively deep analysis and gross oversights.

I started off well, solving the first position with little difficulty (white to move):

1. Nf6+ Qxf6 2. Bh7+ Kh8 3. Bg6+ (key point: blocks Q from coming back to the defence) Kg8 4. Rh8+ Kxh8 5. Qh5+ Kg8 6. Qh7#

So, after calculating a mate-in-6 I felt pretty good going into the next position (Black to move):

This example revealed a couple weaknesses in how I analyze. First, the two most obvious candidate moves are 1...Qxd1+ and 1...Nf6+ (both the most forcing move possible: a check). I analyzed the latter move first, and when I arrived at a satisfactory answer I stopped there without analyzing 1...Qxd1+. I usually try to keep in mind the old advice "when you've found a good move, look for a better one". However, in tactical puzzles I've noticed a tendency to think, "oh I found the answer" and stop my analysis there when in a real game I would think a bit more.

I analyzed 1... Nf3+ and found that Black wins after 2. Bxf3, 2. Kh1 and 2. Kf1. However, after analyzing 2.Bxf3 I very quickly thought "and 2. Qxf3 is no different". However, 2... Qxd1+ 3. Qxd1 Re1+ doesn't work because of 4. Qxe1 (whereas after 2.Bxf3 and 3.B (or N)xd1 the e1 square isn't covered and 3...Re1 will mate. It's rather shocking that I dismissed 2.Qxf3 as leading to an identical result as 2.Bxf3 with about 1 second of thinking.

Correct is 1...Qxd1+, which the reader can work out leads to mate, e.g. 2. Nxd1 Nf3+ 3. Qxf3 Re1+ 4. Bf1 Rxf1#.

The next position I solved easily. White to move:

1. Qxf4 Bxf4 2. Rxh5 gxh5 3. Rxh5 *

I was then brought back down to earth in the next example. Curiously, I analyzed a double capture on h6 that failed, and missed a different capture on h6 that worked. White to move:

After 1.Rh8+ Kg6 I analyzed 2. Rxh6+ 2... Kxh6 (a secondary oversight: 2... gxh6 would also defend, but ...Kxh6 is stronger) 3. Rh8+ Kg6 4. f5+ exf5 5. Qh6+, which would mate except that there's still a g-pawn: 5... gxh6! -+

Correct, however, is 2. f5+ exf5 3. Qxh6+! because here after 3...gxh6 4. Rag8#

At this point I'm batting .500. I get the next position "half-right" (White to move):

The principal variation was clear to me: 1. Bxf6 Bxf6 2. Qxh7+ Kxh7 3. Rh5+ Kg8 4. Ng6 with mate to follow.

However, I had trouble with 1... gxf6. I calculated 2. Qg4+ Kh8 3. Rd3 Rg8 4. Nxf7#. Alas, 3...Nxe5!-+ defends, as well as 3...fxe5+/=.

The book solutions include both 2. Qh6 (which seems more straightforward, e.g. 2...Nxe5 3. Rh5) and 2. Rh5, e.g. 2...Nxe5 3. Rxh7 Ng6 4. Qh6. If instead 2... fxe5 (so the bishop defends after 3. Rxh7? Bf6), White has 3. Qf5!

I may charitably still been batting .500 after that example, but not after this position. Black to move:

This is another example where I had two moves to consider, and stopped after analyzing just one. I thought I had found a clever tactic with 1... Rh3, and indeed after both 2. gxh3 and 2. g3 Black mates. There was just one little problem: 1...Bxh3. On occasion, I overlook that bishops can indeed move backwards.

Yusupov mentions in the "Candidate Moves" chapter: "Accurately calculating over the distance of the first few moves is more important than the capacity to calculate long variations". This oversight certainly supports that remark.

Correct is 1...Nf3!, which leads to mate.

This should give the reader both an idea of the level of Yusupov's book, and the uphill battle I face in improving my ability to calculate.

1 comment:

Admin said...

I am a B-class player. Proud of myself