Calculation of Variations

Calculation of Variations - The working out of chains of moves without physically moving the pieces.

En prise - A piece or pawn that is undefended and can be captured.

Tactics - Maneuvers that take advantage of short-term opportunities.

"The really good players keep a balance between mastering their understanding of positional chess while continually staying sharp tactically and precise in calculation." - GM Susan Polgar

What technique(s) do you employ to be precise enough in your calculation to not leave a piece en prise? What chess book(s) or exercises helped you in becoming more precise in calculation? Thanks!

My current method takes too much time on the clock. Too much trial and error. Example: "Let's see, takes-takes-takes-takes...oops...that won't work. I push my pawn, my opponent captures my pawn, I recapture, my opponent forks my rook and queen...arg! The clock keeps ticking..." 

Thanks BorgQueen. I agree. Much practice is required. There seems to be no short cut regarding calculation. 

Chess.com's tactics trainer is awesome. I wonder if it would be possible for them to develop a calculation trainer? Perhaps a five move sequence puzzle to solve without hanging a piece?

Alexander Kotov's Think Like a Grandmaster, Jon Tisdall's Improve Your Chess Now, John Nunn's Secrets of Practical Chess and Andrew Soltis' How to Choose a Chess Move are some books that offer practical advice on how to organize your thoughts when calculating in real game situations.

Aim for accuracy and try to establish an evaluation at the end, then trust yourself. 

To be accurate really helps, just go SLOW and find the best moves for your opponent too.  Any lines that allow the knight fork immediately throw out -- obviously you'll have evaluated that as losing and so now trust yourself and don't calculate that line again (unless you're not sure, so maybe 1 more time).  I remember I used to calculate all over the place and the same lines over and over as if checking it again may make it work this time.

So instead of takes takes takes takes when in the game your opponent surprises you with a fork you didn't see, just look at "takes" (one half move) now look at your opponent's different moves, what do you think he wants to do?  Ok he wants to take back so now you have "takes takes" etc.  Of course you have to have a tournament length time control for this to work but this is how you do it -- slow, accurate, evaluate it, trust yourself. 

Of course nearly impossible to immediatly do, so like borg queen said lots of practice :)  Also with tactics for sure because I'm guessing a lot of that re-calculation is trying to make sure you didn't miss tactics.

Kotov also talks about Blumenfeld's rule where you try to take a last look at the position with fresh eyes looking for elementary mates or en prise pieces before you actually play your move.  This should help prevent you from making obvious mistakes.

One key technique to improve is to go over your own losses with an eye to discovering what kind of mistakes you typically make, for example, if you are playing too aggressively or not aggressively enough, or if you are missing particular types of combinations such as skewers, loose pieces or long distance queen moves.

All outstanding authors. I'll place them on my wish list. Thank you!

So instead of takes takes takes takes when in the game your opponent surprises you with a fork you didn't see, just look at "takes" (one half move) now look at your opponent's different moves, what do you think he wants to do? - Orangehonda

Thinking in half-moves did not enter my mind until you mentioned it. My method has been to run long sequences in hopes of making sure not to hang a piece. I see now where my thinking is flawed in this regard.  I missed two forks in my last cc game because I had tunnel vision over one weak square and how to repair it!

Great answer! I saved it in my chess tips folder. Thank you.

I especially like the idea of "Xray" powers. Excellent point.

 Out of those, I just have Kotov, and it was phenomenal.