+ my $tags = $pgn->tags();
+ my $pos;
+ if (exists($tags->{'FEN'})) {
+ $pos = Position->from_fen($tags->{'FEN'});
+ $pos->{'player_w'} = $white;
+ $pos->{'player_b'} = $black;
+ $pos->{'start_fen'} = $tags->{'FEN'};
+ } else {
+ $pos = Position->start_pos($white, $black);
+ }