Greetings,

bragesjo
I'm often surprised at the lack of knowledge shown by strong players - even when you don't play well!

Here's an example from one of my games in the UK which I played several years ago...

Event: County Championship
Round ?: Bucks v Kent
Date: 1 Feb 1997
White: Chris Rice (BCF 185/ELO 2080)
Black: James Burke
Result: 0-1

1. e4, c5; 2. Nf3, d6; 3. d4, cd; 4. Nxd4, Nf6; 5. Nc3, g6; 6. Be3, Bg7; 7. f3, Nc6; 8. Qd2, 0-0; 9. 0-0-0, d5; 10. Qe1 [1], e5; 11. Nxc6, bc; 12. ed, cd [2]; 13. Bg5, d4 [3]; 14. Ne4 [4], Qb6 [5]; 15. Bc4, Rb8; 16. Bb3 [6], Nxe4; 17. fe, Be6; 18 Kb1, Rfc8; 19. Bc1 [7], Bxb3; 20. ab [8], a5; 21. Rf1, a4; 22. ba?! [9], Qc6; 23. Rf2(?) [10], Qxa4; 24. Rd3, Rb7; 25. c3, Ra8; 26. cd, Qa1+; 27. Kc2, Rxb2+; 28. Kd1?? [11], Qa4+ [12];

[1] On returning to my flat in Bucks, I checked my Dragon books and found this in Sicilian Dragon: Classical & Levenfish Variations by Sapi/Schneider (Batsford, 1990) - Chapter 48, pages 201-203.
10. Qe1!? is described as a "new idea from the Soviet player Dvoiris".
By the way, in case you're wondering how this could be in a Classical/Levenfish book - this was the first of a two-volume work in which they'd included (some of) the 9. 0-0-0 lines. The second volume covered the rest of the Rauser (Yugoslav) Attack.
[2] This is described as "perhaps critical".
[3] The main variation is given as 13. ..., Be6; 14. Bc4, Qc7;  15. Bxf6, dc; 16. Bxg7, Kxg7; 17. Nd5, Bxd5; 18. Rxd5, Rfe8; 19. Qc3, Rad8; 20. Rhd1, Rxd5; 21. Rxd5, Kg8! "with counterplay in the major piece ending, though White is a little more comfortable." Also, 14. ..., Qb6; 15. Bxf6, Bxf6; 16. Bxd5, Rab8; 17. Bb3, Rfc8; "offered some play for the pawn", Dvoiris-Stanich, USSR, 1987 and 14. ..., Qb8; 15. Bxf6, dc!?; are possible.
[4] Deviating from 14. Qxe5, h6; 15. Rxd4!?, Bd7; 16. Bh4!, g5; 17. Bg3, Nh5; 18. Qd6, Bxd4; 19. Qxd4 (Golubev). Another possibility is 14. ..., Ng4; 15. Qxg7+, Kxg7; 16. Bxd8, Rxd8; 17. fg, Bxg4; 18. Rd3, dc; 19. Rxd8, Rxd8; 20. bc, Rd1+; 21. Kb2, Be2; (-+) If 19. bc, Rac8 (unclear). This 14. ..., Ng4 variation was my own analysis after the game, by the way - not from the book.
[5] Obviously, 14. ..., Be6??; 15. Qh5 (+-).
[6] 16. b3?! (-+)
[7] Black threatened 19. ..., Rxc2+; 20. Kxc2, Bxb3+; 21. ab, Qxb3+; 22. Kd2, Qxb2+; 23. Ke3, Rb3+; winning easily.
[8] 20. cb!? was worth consideration.
[9] Not the best! 22. Qf2(!) or 22. b4!? was surely to be tried.
[10] And again, not the best. 23. Qf2(!) was required.
[11] At least 28. Bxb2, Qxe1 keeps him in the game - for what it's worth!  
[12] Obviously 29. Rc2, Qxc2 is mate.

At the time, I was quite pleased that I'd found/played the right ("book") moves following 10. Qe1!? up to my 13^th move over the board!  

Years earlier, in a tournament in Ireland, I reached a position in the Classical Dragon where my opponent - a 2000-2100 player - played f4 allowing the queen sacrifice for three minor pieces. Having played ..., Ng4, my opponent admitted that he was lost as to what to do! This, over the board!  

I didn't admit it, but I too was somewhat uncertain of the correct continuation, since not many play the Classical - it's usually the Rauser (Yugoslav)!   And the queen for three minor pieces wasn't something I'd studied that much either. Sadly, I lost in the end   - I'll have to find it and perhaps post it - if anyone's interested.

Kindest regards,

James