Botvinnik Semi-Slav, The (Pedersen)

THE MAIN liNE: 17 a3 23
as there is no good defence to 31l:[e1 +.
Afterwards, however, I.Sokolov suggested
that White has nothing more
than a perpetual check after 28 ... 'fi a5 !
29 .l:txd8+ 'fixd8 30 l:tc8 .l:td5 31
.l:txd8+.l:txd8 32 'iib5+l:[d7 33 'iib8+.
b12) 25 "ii'a8!. With this amazing
move White combines several threats
and Black cannot parry all of them:
b121) 25 ... "ii'a5 26 l:td4+ ltd5 27
:'xd5+ "ii'xd5 (27 ... exd5 28 'fic8+~d6
29 liJc5 +-) 28 "ii'xa7+ ~e8 29 liJb6
'iib5 30 l:td1! and White wins. There
is mate in a few moves starting with a
sacrifice on d8.
b122) 25 ... "ii'xa4? 26 l:td4+ l:[d5 27
"ii'c8+ ~e8 28 .l:txd5 exd5 29 l:[e1+
mates.
b123) 25 ... ~e8 is the best defence,
but White is winning after 26 .l:tc8 :'d5
27 "ii'xa7 (D).
The threat is the artistic liJb6-a8-
c7+. Here are a few lines to illustrate
how bad things really are:
b1231) 27 ... ltd7 28 liJb6!! lha7?
29 :'xd8+ ~xd8 30 :'c8#.
b1232) 27 ... :'h6 28 liJb6 :'d2 (or
28 .. Jbf6 29 liJxd5 "ii'xd5 30 :'xdS+
'iixd8 31 "ii'a4+ +-) 29 liJaS ltd7? 30
liJc7+ :'xc7 31 :'xd8+ 1-0 Lazarev­
Dgebuadze, Werfen 1993 .
b1233) 27 ... .l:thh5 is no better. Maksimenko-Scherbakov,
Aalborg 1993
now continued 28liJb6 l:td2? 29 :'8c7!
(this is possible as Black is not attacking
the f6-pawn) 29 ... .lld6 30 l:[e7+
~f8, and now the simplest would have
been 31l:[xf7+!.
b1234) 27 ... 'fid7 28 :'xd8+! "ii'xd8
29 liJb6 l:td1+ and now 30 ~g2? is
mistakenly given as winning for White
by Maksimenko, but I do not see anything
convincing for White after if
Black replies 30 ... "ii'xb6!. However,
do not despair, as White wins with 30
.l:txdl! 'fixd1+ 31 ~g2 .llc5 (forced)
32 'fia8+ 'fid8 33 "ii'c6+ ~f8 34
'fixc5+ ~e8 35 'fib5+ ~f8 36 "ii'xb4+
~e8 37 "ii'b5+ ..ti>f8 38 "ii'c5+ ~e8 39
'fic6+ ~f8 40 b4!; e.g., 40 ... lth5 41
liJd7+ ~g8 42 b5 l::td5 43 "ii'c4! :'g5
(43 ... 'fia8 44 'fie4 'fib7 45 liJc5 "ii'a8
46 b6 'fif8 47 b7 +-) 44 h4 ':g6 45
'fic6, etc.
b2) 23 l::tdl!? was Knaak's idea,
tested in a game by Piket, and while it
may well be rather strong, I find the
above analysis convincing enough, so
I will restrict myself to giving the
Piket game: 23 ... liJe5 24ltc5! liJxg4
(24 ... .txc5 25 lhd5+ ~e8 26 ':xe5
.llxt2+ 27 ~xt2 "ii'xe5 28 h4 and White
wins) 25 ':dxd5+ exd5 26 :'xb5 with a
clear advantage for White, Piket­
Nalbandian, Biel IZ 1993.