[FEN "r2qk2r/ppp3pp/2bp1n2/2b1p3/2Q1P3/5N2/PPP2PPP/RNB2RK1 w kq - 0 10"]

{%17{#MARKERS - N  #B(8/8/8/8/8/8/8/8)  #S(8/8/8/2DO1DO3/8/8/8/8)  #C(8/8/8/8/8/8/8/8)  #F(8/8/8/8/8/8/8/8)  MARKERS#}}
10.Nxe5 {%16I} Bxf2+ 11.Rxf2 {%1610} dxe5 12.Nc3 Qe7 13.Be3 a6
14.Rd1 $16 {Minchev Valentin  - Stefanov Stefan,
 *

[FEN "N2q1bk1/pp1b1r1p/3p1nn1/P2Pp3/1P2Pp2/5Pp1/4BBPP/2RQNRK1 b - - 0 21"]

{%17{#MARKERS - N LA4(f6:h5) LA4(h5:g3)  #B(8/8/8/8/8/8/8/8)
#S(8/8/8/8/8/8/8/8)  #C(8/8/8/8/8/8/8/8)  #F(8/8/8/8/8/8/8/8)  MARKERS#}}
21...Nh5 {! %16I} 22.Kh1 ( 22.Bxa7 Qh4 {%16I} 23.h3 Bxh3 {%16I}
24.gxh3 Qxh3 {%16I} 25.Rf2 gxf2+ {%16I} 26.Kxf2 Nh4 27.Bf1
( 27.Nc2 Rg7 28.Ke1 Rg2 29.Qd3 Ng3 $19 ) Qh2+ {%16I} 28.Ng2 Rg7
$17 {%16I} ) gxf2 {%16I} ( 22...Qh4 {?} 23.Bg1 ) 23.Rxf2 Ng3+
{! %16I} 24.Kg1 ( 24.hxg3 fxg3 $19 ) Qxa8 25.Bc4 {%17{#MARKERS - N LA4(a7:g1)  #B(8/8/8/8/8/8/8/8)  #S(8/8/8/8/8/8/8/8)  #C(8/8/8/8/8/8/8/8)  #F(8/8/8/8/8/8/8/8)  MARKERS#}}
a6 {! ('with the idea'Qa7 'diagonals'a7-g1) %1680} 26.Qd3
( 26.hxg3 fxg3 27.Rb2 Qd8 28.Kf1 ( 28.f4 Rxf4 29.Qd3 Bh6 30.Rcb1
( 30.Rc3 Qh4 31.Qxg3 Qxg3 32.Rxg3 Rxe4 33.Be2 Bf4 $17 ) b5 31.Bb3
Qc7 32.Nf3 Nh4 ) Bh6 29.Ke2 Qg5 $17 ) Qa7 {%16I} 27.b5
( 27.Rcc2 {%17{#MARKERS - N LA4(f8:e7) LA4(e7:h4)  #B(8/8/8/8/8/8/8/8)
#S(8/8/8/8/8/8/8/8)  #C(8/8/8/8/8/8/8/8)  #F(8/8/8/8/8/8/8/8)  MARKERS#}}
Be7 {'with the idea'Bh4} $19 {%16I} ) axb5 {%16I} 28.Bxb5 Nh1
{! 0-1, Piket Jeroen - Kasparov Gary, Tilburg 1989 It %1620} *

##</code><code>##

#!/usr/bin/perl 
# Remove extra text from a PGN or Text-file.
# Aufruf: perl removeEK4.pl  In.txt  > Out.txt

use strict;
use warnings;
my $regex = '%17\{#MARKERS.*MARKERS#}';
my $line = do { local $/;  <>; }; 
$line =~ s/\n/ /g;
$line =~ s/$regex/ /gi;
$line =~ s/ (\d+\. |\[)/\n$1/g;
print $line;

##</code><code>##

[FEN "r2qk2r/ppp3pp/2bp1n2/2b1p3/2Q1P3/5N2/PPP2PPP/RNB2RK1 w kq - 0 10"]
10.Nxe5 {%16I} Bxf2+ 11.Rxf2 {%1610} dxe5 12.Nc3 Qe7 13.Be3 a6 14.Rd1 $16 {Minchev Valentin  - Stefanov Stefan,  *  

[FEN "N2q1bk1/pp1b1r1p/3p1nn1/P2Pp3/1P2Pp2/5Pp1/4BBPP/2RQNRK1 b - - 0 21"]
21...Nh5 {! %16I} 22.Kh1 ( 22.Bxa7 Qh4 {%16I} 23.h3 Bxh3 {%16I} 24.gxh3 Qxh3 {%16I} 25.Rf2 gxf2+ {%16I} 26.Kxf2 Nh4 27.Bf1 ( 27.Nc2 Rg7 28.Ke1 Rg2 29.Qd3 Ng3 $19 ) Qh2+ {%16I} 28.Ng2 Rg7 $17 {%16I} ) gxf2 {%16I} ( 22...Qh4 {?} 23.Bg1 ) 23.Rxf2 Ng3+ {! %16I} 24.Kg1 ( 24.hxg3 fxg3 $19 ) Qxa8 25.Bc4  a6 {! ('with the idea'Qa7 'diagonals'a7-g1) %1680} 26.Qd3 ( 26.hxg3 fxg3 27.Rb2 Qd8 28.Kf1 ( 28.f4 Rxf4 29.Qd3 Bh6 30.Rcb1 ( 30.Rc3 Qh4 31.Qxg3 Qxg3 32.Rxg3 Rxe4 33.Be2 Bf4 $17 ) b5 31.Bb3 Qc7 32.Nf3 Nh4 ) Bh6 29.Ke2 Qg5 $17 ) Qa7 {%16I} 27.b5 ( 27.Rcc2  Be7 {'with the idea'Bh4} $19 {%16I} ) axb5 {%16I} 28.Bxb5 Nh1 {! 0-1, Piket Jeroen - Kasparov Gary, Tilburg 1989 It %1620} * 

##</code><code>##

[FEN "r2qk2r/ppp3pp/2bp1n2/2b1p3/2Q1P3/5N2/PPP2PPP/RNB2RK1 w kq - 0 10"]  { } Be7 {'with the idea'Bh4} $19 {%16I} ) axb5 {%16I} 28.Bxb5 Nh1 {! 0-1, Piket Jeroen - Kasparov Gary, Tilburg 1989 It %1620} *