Hi,
I was with an IM player and were studing my games for a few days. To continue my training he said my problem is calculation. He said to me I dont need tactic books as I am very creative and good in recognizing patterns. What I need, he said, is to put a very difficult possition in fron of me, with lots of variations and combinations and analyze them in depth.
Do you know of any book with this kind of possitions?
Thanks
FS

Dan Heisman recommends something similar on his web site. He's got 3 or 4 example positions that he says to study for a long time and write down everything you can see. I need to try some of those exercises myself.

Something I thought of for picking out positions to do this: Pick any game in any book of annotated master games. Skim the game visually without actually reading the moves or text, just to pick out the biggest block of annotation after a single move, with the most move variations listed. Play out the game up to that point, then analyze that particular position as deeply as you can, writing down everything you see. Then compare what you wrote to the annotator's comments when you're done.

--Fromper

I am beginning to work on this area in my game. Funny enough, sometimes it is not even difficult positions, it's the goal of looking beyond the obvious move and go even further. I'm reading "excelling at chess calculations" by Jacob Aagard. I've just started but it seems like a good one. I like Fromper's idea on master games. I'm going to try it and see if it helps.

An additional good source is Dvoretsky's series. He offers positions related to all phases of the game and provides some structure for your study as well.

I hear his Analytical Manual is actually exactly what he is looking for. Crash and Abba both own the book, so they can say more about it than I can.

Dvoretsky's Analytical Manual.
Tal's Life and Games
Gary Kasparov's Greatest Games Vol 1 and 2 by Stohl
Kasparov's Fighting Chess 1993-1998 by Karolyi and Aplin
Kasparov's Fighting Chess 1999-2005 by Karolyi and Aplin
Secrets of Grandmaster Chess by Nunn

There are many others...

Vladimir Drkulec

Think Like a Grandmaster (by Kotov) is pretty good as well.

John Nunn has a new problem book out. I forget the exact name, something like 200 problems in it (but more of the calculation style than pattern style)

Also, for something completely different yet still related, Silman's How to Reassess Your Chess is one of the best in analyzing middlegame/endgame positions.

Speaking of endgame books, while Dvoretsky's middle game books have been mentioned as helpful for analysis, one should also mention his Endgame Manual. Despite being meant for endgames, the discipline needed to analyze carefully an endgame position is the same discipline you need for middle game analysis

Also, if you know that a certain endgame is winning or is a draw, that will influence how you play the middlegame.