An example of how to think & evaluate the position correctly (also taken from my first book “The Very Unusual Book About Chess”)

 [Event "First Saturday Budapest"]  [Site "?"]  [Date "2000.??.??"]  [Round "?"]  [White "Dembo, Y (WIM)."]  [Black "Driamin, D (IM since 2003)"]  [Result "1-0"]  [WhiteElo "2342"]  [BlackElo "2281"]  [Annotator "Variations by Dembo,Y"]  [SetUp "1"]  [FEN "r3kn1r/1p1bbp2/4p3/3pP1p1/p2q2P1/P2B4/1P3P2/R1BQRNK1 w kq - 0 19"]  [PlyCount "47"]  [EventDate "2000.??.??"]   {It is hard to believe, but the opponents reached this complicated position on  the 19th move only ten minutes after the start of play. This variation of the  French Defence, involving the sacrifice of my d-pawn, had occured before in my  games. My Muscovite opponent knew that of course and had prepared for the game  very meticulously; in particular he spent about one-and-a-half minutes for the  first twelve moves... Naturally, this did not appeal to me but I did not want  to refrain from my variation. I had great faith in my ability to checkmate the  opponent's uncastled king! For this it is necessary to bring about a very  sharp and complicated position...  #} 19. Be3 $1 {The first move leading to  this aim. At last my opponent thought for 40 minutes! Before this move White  already was a pawn down and now offers two more; Black even has the choice!  Now there is no question "to take or not?": the black queen has no other moves.  The question is only which pawn to take and what to do after that. After  prolonged thought Black decided to take the central pawn, an understandable  decision.} Qxe5 (19... Qxb2 20. Rb1 Qxe5 21. Bf5 $13) 20. Bf5 $3 {After the  game my opponent admitted having missed this move - also understandable...  At  this moment 30-35 chessplayers gathered around our table and one grandmaster  said to my father and coach: "your daughter is either a genius or crazy!" "Of  course the first!" was the prompt answer of my father, but his hands were  still shaking even some hours after the game, due to the emotional strain...  White has achieved her aim: the position is becoming totally crazy. White's  idea is now Bd4 or Bxg5.  Here Black once again sank into thought, calculating  several variations; as a result he ended up in serious time-trouble.} Rh4 $5 {  An interesting move. But what about material? How will the position be after  mutual captures?} 21. Bxg5 Qxb2 22. Bxh4 Bxh4 {The captures have finished, so  let's sum up!  For WHITE:  1) the material balance: White has a rook against a  bishop and two pawns.  2) the white king is deprived of protection and the  f-pawn is under attack, but there is no way for Black to increase the pressure  on it.  3) the bishop on f5 is very unusually but nicely placed, but it is not  clear how to make use of it.  4) the white queen and the rook on a1 are out of  play.  For BLACK:  1) the material situation is OK.  2) Black has the  bishop-pair.  3) the queen and the Bh4 are very active. The f2-square in  particular can become a very dangerous point of intersection.  4) the rook and  the knight are inactive.  5) the Bd7's situation lies somewhere in between.  6)  but the main feature of the position is the king on e8. It is true though that  an immediate attack against it is not apparent. Therefore the conclusion is:  it is necessary to improve the activity of my pieces.} 23. Qf3 {There are  three ideas behind this move:  1) the queen is more active now;  2) the f-pawn  is protected;  3) the d1-square can be used by one of the rooks (I don't know  which yet!).  And we come to a new "Dembo-rule": "if there are two or more  ideas behind your move, then it is usually a good move!"} Qf6 24. Rac1 $6 {I  am trying to prevent the black king from castling, but 24.Ng3!? with an idea  of Nh5 was much stronger. Of course it would have been a blunder to play 24.  Qd5?? because of 24...Qxa1 - "blow back"!} Bc6 {My opponent, just like me,  didn't see the move 24...Kd8. It is hard to say how the game would have ended  after that move... But Black was already in serious time-pressure.} 25. Ng3 {  The pin on the f-file is very dangerous for White, as Black constantly has at  his disposal threats to win the bishop or exchange queens. Therefore the  knight is in a hurry to drive away the black queen.} Nd7 {Black brings his  knight into the game as well.} (25... Qh8 26. Nh5 Be7 27. Bb1 Nd7 28. Qe3 $13)  26. Nh5 Qg5 27. Nf4 {The knight's route from b1 to f4 was long and complicated,  but it now consitutes a source of danger to the black king.} O-O-O {Black  managed to beat back the first wave of attack. # But a second wave is forming..  .} 28. Nxd5 $1 {##A very interesting idea!} ({Much worse was} 28. Bxe6 $2 fxe6  29. Nxe6 Qf6 $1 30. Qe2 Ne5 31. Nxd8 Nf3+ $17) 28... exd5 (28... exf5 29. Ne7+  Kb8 (29... Qxe7 30. Rxc6+ bxc6 31. Qxc6+ Kb8 32. Rb1+ $18) 30. Rxc6 (30. Nxc6+  bxc6 31. Rc4 Qg6 $1 (31... Qf6 $2 32. Rxc6 Qb2 33. Qf4+ $18) 32. Rb1+ $40)  30... bxc6 31. Rb1+ Nb6 (31... Ka7 32. Nxc6+ $18) 32. Rxb6+ Ka7 33. Ra6+ Kxa6  34. Qxc6+ Ka7 35. Qc7+ Ka6 36. Qc6+ $11) 29. Qxd5 {Now White has rook for two  minor pieces. The genius Mikhail Tal very much liked to bring about and use  this material correlation...} Qh6 {After this move my opponent had 15-20  seconds left until the time-control on move 40. People around the board were  already holding their breath...} ({Instead of 29...Qh6 Black had at his  disposal a brilliant idea, sacrificing a bishop:} 29... Bxf2+ $5 30. Kxf2 (30.  Kf1 Qf4 {Threatening ...Bc5.} (30... Kc7 31. Kxf2 Qf4+ 32. Kg1 Qg3+ $11) 31.  Rxc6+ Kb8 (31... bxc6 32. Qxc6+ Kb8 33. Re4 $16) 32. Rc4 Bd4+ 33. Ke2 Re8+ 34.  Kd1 Rxe1+ 35. Kxe1 Qe3+ 36. Kd1 Qg1+ 37. Kc2 Qf2+ $11) 30... Qf4+ 31. Kg1 (31.  Kg2 $4 Qd2+ $1 $19 {# I don't know which lines my opponent calculated but I am  still curious if he had seen this unique position before making the move 29...  Qh6. What a position! I wouldn't want to lose this way.}) 31... Qg3+ 32. Kf1  $11) ({In case of} 29... Qf6 {I was seriously contemplating 30.Re6 with a  possible draw.} 30. Re6 fxe6 31. Rxc6+ bxc6 32. Qxc6+ Kb8 33. Qd6+ Kc8 (33...  Ka8 34. Be4+) 34. Qc6+) 30. Red1 {It appears that the bishop is about to start  working: 31.Bxd7 is threatened.} Kb8 31. Rxc6 $1 {Unfortunately this last  sacrifice only leads to a draw, but luckily for me my opponent was intent on  winning!} bxc6 (31... Qxc6 $1 32. Qxc6 bxc6 33. Rxd7 (33. Bxd7 Kc7 $19) 33...  Rxd7 34. Bxd7 Kc7 35. Be8 $11) 32. Rb1+ Kc7 (32... Kc8 {would lead to a nice  finish (nice for White, that is!) after} 33. Qe5 $1 $18) 33. Qa5+ {Again  inviting the black king to c8.} Kd6 (33... Kc8 34. Qe5 $1 $18) 34. Rd1+ Ke7 35.  Qc7 Kf8 {My opponent had only a few seconds left, but still dreamt of winning!}  36. Rxd7 Rxd7 37. Qxd7 Qc1+ 38. Kg2 Qxa3 39. Qxc6 Qa2 $4 $138 {A terrible  blunder in time-pressure.} ({After} 39... Kg7 {the position would be equal.})  40. Qh6+ $1 Ke8 41. Qh8+ {Never offer the opponent a tempo!} Ke7 42. Qxh4+ {1:  0 :  After the game my father told me: "I lost some kilograms during these few  hours!" I think I also did...} 1-0