Calculation Training

 That's okay, have fun with this long thread - it is intended to help everyone's calculation. 

puzzle 8:

First candidate line that seems to make sense:

1. Bxg6 xa4

2. xf6 xg6

3. Rae1 (many responses exist here but they all seem to end the same so I will go with the simple Qxe1 since it seems to be blacks best reply, if I am wrong here please let me know)

4. Rxe1+ ...Now this is where it gets interesting between the 4 choices available.

     If ...Kd7 then 5. Re7+ Kc8 (because Kd8 is met with 6. xg7 Rg8, 7. Rxb7+ Ke8, 8. Ne6#) 6. Nd6+ Kd8 since the other option is mate in 1 then 7. Nxb7+ Kc8, 8. Nd6+ Kd8, 9. Nf7+ Kc8, 10. Nxh8 and black is down 2 minor pieces going into an endgame with terrible pawn structure, restricted king and rook. So Kd7 is no good.

     If...Kd8 then 5. xg7+ Kd7 (trying to save losing his rook to a queening pawn) 6. Re7+ which sets up mate the next move anyway with a queening pawn regardless of which square the king moves to so move 4. ...Kd8 is no good.

     If...Kf7 then 5. Re7+ Kf8 (Kg8 is met with 6. Rxg7+ Kf8, 7.Ne5 Ke8, 8.f7+ Kf8 is forced 9. Bf6 and any move black makes here is met with Nxg6#) so back to the line. 6. xg7+ Kg8, 7. xh8=Q+ 8.Rxb7 and black is down 2 minor pieces with terrible pawn structure. So move 4. ...Kf7 is no good.

     Finally, If ...Kf8 then 5. xg7+ Kxg7 (he must recapture to avoid losing in one of the methods above after Re7+) 6. Re7+ Kg8, 7. Rxb7 and white would have 2 pieces for a rook. Black's pawn structure would be destroyed on the queenside and white would have a 3 to 2 pawn advantage on the kingside.

And after contemplating and calculating all of this over a good 2 hours hahahaha, I decided to look it up and I see that I was on something of the right path. Of course, some responses aren't forced in the first few moves that I typed up, but I think the moves in the actual game kind of solve that issue.

Man I do need to practice calculating though, these exercises have proven that to me. Beside the fact that these can be very difficult, I find my focus isn't what it should be in order to calculate lines in a proper amount of time even in less complicated spots.

TBH @tonyklemm 's analyzes gave me an idea. I think the biggest problem in their analyze is after 1.Bxg6 bxa4 2.exf6, black can just castle with 0-0.

With that in mind,  I found following idea: 

1.exf6 bxa4 2.fxg7!(suddenly black king is trapped at the center) Rg8 3. Bf5! Qxc4 4.Rfe1+  Qe6 5. Bxg6! Kd7 6.Rad1+ Kc7 7.Rxe6 fxe6 8. Bf6! 

Great! 2 hours is a lot for sure, but that is the point of this forum - to give calculation practice for those willing to put the time in to improve. 2 hours is a drop in the bucket long-term if you improve a lot because of it: your time is well spent

Avoiding Black from castling is a key idea: I am impressed with your creativity for a Queen sacrifice @Spaceysmile. I looked at your line (and it is impressive calculation), but I wonder what you would do if 5...Bc8 in your line instead of 5...Kd7. Now 6. Rxe6+ is met with ...Bxe6 and a roughly equal position.

Bump. 

Any other attempts at the 8th official puzzle? (currently post #221). Spend some time on the diagram and put calculation practice into effect. Simply analyze your thinking and post in the comments.

Umm I think at the variation I suggested, 5.Rxe6+ fxe6 6.Bxg6+ Kd7 7.Rd1+ Kc7 8. Bf6! goes to same position with avoiding Bc8 opportunity.

Your overall calculation was insightful @Spaceysmile. I'm bumping this thread to give others a chance to attempt this puzzle before I release the game solution/annotations. Of course, feel free to add any other ideas you may have: but you've done quite a bit of analysis already

I like that discussion and Im gonna have a crack at your puzzles: https://www.chess.com/clubs/forum/view/calculation-skills

Cool. Glad to hear it. We are on the 8th official puzzle right now, but feel free to post about previous puzzles if you want (although the answers to those are already posted within this thread).

Wow. Great analysis. I've read through most lines (tackle the rest later) and it looks solid.

p.s. at the end of the post, castling was brought up. In this position, Black DOES still have castling rights. Although I didn't mention this originally (better for the solver to discover this aspect), Black threatening ...O-O and getting a safer King is an important point in this position.

Sorry after 6 kc8 Rf8 and white promotes with checkmate to follow.

For the first one (I missed out those)

I'm gonna solve the others later cz I don't like to post ten messages in a row

Thanks for active participation in this forum @chamo2074

How many problems have been edited untill now ?  It's very long to go through all the 13 pages so maybe a summary would be a good idea.

8 official puzzles have been presented so far. A summary would be a good idea if here was a clean way to post one without it becoming lost in the 13 (currently) pages of comments. If I don't get many responses to the 8th puzzle, then I may give the solution soon and present a 9th puzzle for everyone to attempt.

What is the 8th puzzle ? (-_-)"

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