Calculation Training

When calculating make sure to always look at all checks and captures before considering alternatives. I cover this in my blog. Go check out my profile and blog!

Here is the "9th Official Puzzle" solution. 

very interesting 

This is the "10th Official Puzzle" - I'm curious to hear everyone's thinking/analysis

This position is Black to move. 

Sher vs Kamsky, Dos Hermanas, 2007

That's what I was hoping for

I'm calculating 1. ...Nxg4 2.hxg4; h3 3.Bf3; Ne5 4.Ng3; Qf6 5.Be2; Nxg4 6.Bxg4; Qxa1

This is the first line I see.

EDIT: instead of 3.Ne5 just 3.Qf6 attacks the Ra1 and the Bf3...

EDIT 2: 3.Qf6 4.Bf4; Nxf4 5.Nxf4; Qxf4 6.Qe2? (for instance); Bd4! 7.Rad1; Be5 with the Qh2mat threat. I don't know. In real game I would probably go for 1. ...Nxg4 without much fear and blacks seem just better.

I think kjDG12 may have already solved. They gave a question mark to Qe2 but black threats Bd6 anyway, which I cannot see any defense. Best for white is probably rejecting the sacrifice,  but it is still bad for them.

yeah it's just bad for whites after Nxg4, they doesn't have any material advantage or direct ressource defense it's just over. 

Yes, ...Nxg4 was the first move and it is basically over after that. I was just curious to see just "how far" after one move people would calculate - I guess one could say I kind of threw this one-move puzzle out there as sort of an experiment

I'll search for another puzzle later on: I prefer quality over quantity, but I'll see what I can find. I don't just go with the first puzzle I come across: I sort through several options and choose the ones I like more. 

It's easy

I am happy to announce the "11th Official Puzzle" where it is White to move. Especially with so few pieces on the board, like here, I find this instructional to see how far one can calculate from the initial position, but that is just me  White to move. 

Stefan Schneider, 1956, composition

1.Bb3+; Kf5 only move 2.Kd5 (threatening Bc2mate); h2=Qh1+ 3.f3 (threatening f3xg4mate somehow and Bc2mate); Qg2 (keep both threat in control for now) 4.Bc2+ decoy the queen to depinned the f3 pawn; Qxc2 5.fxg4mate  Everything is forced if I missed anything from blacks' defense.

Really good first try, but Black does have a surprising defense  In your line, 3. f3 can be met with ...Qxf3+! (Black sacrificing the Queen) and then 4. Nxf3 gxf3 and although White may have the advantage, Black's passed pawn is annoying.

I think a change in move-order can do the trick.

1.f3 and

1...gxf3 2.Bb3+ Kf5 3. Kd5  and Bc2

1...Nxf3 2.Bb3+ Kf5 3.Kd5 Ne1/Nd4 4.Ba4 with the idea Bd7

1...h1Q 2.f5+ Kxe5 3.f4#

1...Ne2 2.Bb3+ Kf5 3.fxg4+ Ke4 4.Bd5+ Ke3 5.f5+ white wins with marching f-pawn 

1...Nh3 2.Bb3+ Kf5 3.fxg4+ Ke4 4. Bd5+ Ke3 5. Bh6 Nf2 6. f5+ and h1 is under control.

I think after 1.f3; Nxf3 2.Bb3+; Kf5 3.Kd5 just Nxg5 and  4.Bc2+is met by Kxf4 and it's not winning at all.

For puzzle 11, wouldn't the main issue be to simply stop blacks pawns and then play a easy win afterward? 

1. Be4 Nf3 2. Nxf3 h1=Q 3. Nd4+ and after the king moves take the queen.

This means black can't block the bishops defense of the queening square with his knight (if he takes the knight with his g-pawn then his h-pawn would never queen anyway). Blacks g-pawn is hanging in the case that black doesn't move his knight to protect the diagonal that white's bishop protects.

Edit: Also, considering black's king is completely paralyzed, the only legal responses black has to Be4 are

1)Ne2 which doesn't seem to offer much and also lets white take the g-pawn and then the h-pawn soon after

2)Nh3 which does the same thing Ne2 does

3)h1=Q which just loses the threat black posed

4)g4-g3 pawn push which helps white even more, undoubling the pawns and not allowing the desperate counter-play offered in the line above

and

5) Nf3 which seems to be refuted in the line provided above.

Bump. No one has solved the "best line" so far  

p.s. I didn't want to give clues earlier IM @pfren, but the line is much more spectacular and forcing a win compared to 1. Be4 only. When the solution is revealed, I think even you will agree that the solution is more satisfying than 1. Be4 (although that move is also "winning" for White I easily admit).

This has to be one of the most beautiful puzzles I've worked on.

The key to solving the puzzle lies in noticing the position of the black king. Actually I worked on the puzzle a bit when the puzzle was originally posted, first moves I saw 1.Bc2+ and 1.Be4 which as @pfren mentioned just seemed to be clearly winning. Other members had done a great job analyzing those moves so I figured the work was done.

I only looked at the position again because @KeSetoKaiba mentioned there was a beautiful solution. And that was how I found this amazing line which is pretty much all forced.

1.Ba4!(threatening mate with Bd7) Kf5

2.Bd7+ Ke4

3.Be8!(threatening mate with Bg6) Kf5

4.Bg6+ Ke6

5.Bh5!(the mate threats continue!) Kf5

6.Bxh4+ Ke4

7.Bd1! Kf5

8.Bc2+ Ke6

9.f5+! Kxe5

10.f4#

Great solving @Magneto616 - yes that is the beautiful solution to this endgame composition. Also, it is a forced checkmate as you said: much better than simply a "winning" move like 1. Be4, which does not guarantee victory. Glad you enjoyed this puzzle

Can  you send a chess diagram. Would make it clearer and more beautiful