diff --git a/.gitignore b/.gitignore
index dc11994..b3380b9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 p[0-9].pl
 p[0-9][0-9].pl
 notes.txt
-#*
\ No newline at end of file
+#*
+save.txt
\ No newline at end of file
diff --git a/LPST.pm b/LPST.pm
index d77325c..681ee2b 100644
--- a/LPST.pm
+++ b/LPST.pm
@@ -1,5 +1,7 @@
 #!/usr/bin/perl
 
+package LPST;    
+
 use warnings;
 use strict;
 
diff --git a/MNU.pm b/MNU.pm
index 87f4393..04aaf82 100644
--- a/MNU.pm
+++ b/MNU.pm
@@ -1,5 +1,7 @@
 #!/usr/bin/perl
 
+package MNU;
+
 use warnings;
 use strict;
 
@@ -7,23 +9,96 @@ use lib "./";
 use NTVL;
 use LPST;
 
-package MNU;
+use Try::Tiny;
+
+my $SAVE_FN = "save.txt";
+
+sub roll_back($){
+    my @arr;
+    my $game_str = shift;
+
+    @arr = split(/\n/, $game_str);
+
+    if(scalar @arr == 1){
+	return "";
+    }
+    return join("\n", splice(@arr, 0, -1))."\n";
+}
+
+sub eval_game_str($$){
+    my ($b, $game_str) = (shift, shift);
+    try {
+	NTVL->f1($b, $game_str);
+	disp_board($b);
+    } catch {
+	warn "invalid move: $_";
+	$game_str = roll_back($game_str);
+    };
+    return $game_str;
+}
+
+sub disp_board($){
+    my $b = shift;
+    $b->disp_board();
+}
+
+sub load(){
+    my $game_str;
 
-sub prompt(){
+    $game_str = "";
+    open FILE, "<".$SAVE_FN or die "couldn't open save file";
+    while(<FILE>){
+	$game_str .= $_;
+    }
+    close FILE;
+    
+    return $game_str;
+}
+
+sub save($){
+    my $game_str = shift;
+    open FILE, ">".$SAVE_FN or die "couldn't open save file";
+    printf FILE "%s", $game_str;
+    close FILE;
+    
+    return $game_str;
+}
+
+sub parse_cmd($){
+    my $in = shift;
+    return -1 if $in =~ /^q(uit)?$/i;
+    return 1 if($in =~ /^save$/i);
+    return 2 if($in =~ /^load$/i);
+    return 0;
+}
+
+sub prompt($){
+    my $game_str = shift;
+    
     printf("> ");
     my $in;
     $in = <STDIN>;
     chomp $in;
     
-    return $in;
+    return "QUIT" if(parse_cmd($in) == -1);
+    return save($game_str) if parse_cmd($in) == 1;
+    return load() if parse_cmd($in) == 2;
+    
+    $game_str .= $in."\n";
+    return $game_str;
 }
 
-sub loop(){
-    my $in = prompt();
 
-    return 0 unless $in;
-    return 0 if $in eq "quit";
-    return 1;
+sub loop($$){
+    my ($class, $game_str) = (shift, shift);
+    my $in;
+
+    $b = LPST->new();
+    $game_str = eval_game_str($b, $game_str);
+    printf("%s\n", $game_str);
+
+    $game_str = prompt($game_str);
+    return $game_str;
 }
 
 return 1;
diff --git a/NTVL.pm b/NTVL.pm
index 0a7a44a..28f727a 100644
--- a/NTVL.pm
+++ b/NTVL.pm
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 
-package main;
+package NTVL;
 
 use warnings;
 use strict;
@@ -17,7 +17,6 @@ my $SACRIFICE = 0b00001000;
 my $DRAW      = 0b00010000;
 my $FT        = 0b00100001;
 
-package NTVL;
 
 sub is_summon($){
    return $_[0] =~ /\*/ ? $SUMMON : 0;
diff --git a/drv.pl b/drv.pl
index 66c0644..b0c71b9 100644
--- a/drv.pl
+++ b/drv.pl
@@ -6,7 +6,11 @@ use strict;
 use lib "./";
 use MNU;
 
-while(MNU->loop()){
-    
+my $game_str;
+
+$game_str = "";
+
+while(($game_str = MNU->loop($game_str)) ne "QUIT"){
+    # printf("XXXX%s\n", $game_str);
 }
 
diff --git a/test.pl b/test.pl
index 387015e..0e1ab53 100644
--- a/test.pl
+++ b/test.pl
@@ -9,25 +9,49 @@ use LPST;
 
 my $ns0;
 
+# $ns0 = "";
+# $ns0 .= "A I Im Au H\n";
+# $ns0 .= "A S Im Rc It\n";
+# $ns0 .= "Aa1*, Ab1*, Ac1*, Ad1*, Ae1*, Qf1*, Ag1*, Ah1*, Ai1*, Aj1*, Ak1*, Ad2*, Ai2*, Aj2*, Ak2*, Ad3*\n";
+# $ns0 .= "Aa11*, Ab11*, Ac11*, Ad11*, Ae11*, Qf11*\n";
+# $ns0 .= "Aa1a2\n";
+# $ns0 .= "Qf11g11\n";
+# $ns0 .= "Aa2a3\n";
+# $ns0 .= "Qg11f10\n";
+# $ns0 .= "Aa3a4\n";
+# $ns0 .= "Qf10e10\n";
+# $ns0 .= "Aa4a5\n";
+# $ns0 .= "Qe10d10\n";
+# $ns0 .= "Aa5a6\n";
+# # $ns0 .= "Qd10e9\n";
+
+
 $ns0 = "";
-$ns0 .= "A I Im Au H\n";
-$ns0 .= "A S Im Rc It\n";
-$ns0 .= "Aa1*, Ab1*, Ac1*, Ad1*, Ae1*, Qf1*, Ag1*, Ah1*, Ai1*, Aj1*, Ak1*, Ad2*, Ai2*, Aj2*, Ak2*, Ad3*\n";
-$ns0 .= "Aa11*, Ab11*, Ac11*, Ad11*, Ae11*, Qf11*\n";
-$ns0 .= "Aa1a2\n";
-$ns0 .= "Qf11g11\n";
-$ns0 .= "Aa2a3\n";
-$ns0 .= "Qg11f10\n";
-$ns0 .= "Aa3a4\n";
-$ns0 .= "Qf10e10\n";
-$ns0 .= "Aa4a5\n";
-$ns0 .= "Qe10d10\n";
-$ns0 .= "Aa5a6\n";
-# $ns0 .= "Qd10e9\n";
+$ns0 .= "A I H It N\n";
+$ns0 .= "A I H It N\n";
+$ns0 .= "Ac3*, Qd3*\n";
+$ns0 .= "Ac11*, Qd11*\n";
+    
 
-$b = LPST->new();
 
+sub roll_back($){
+    my @arr;
+    my $game_str = shift;
+
+    @arr = split(/\n/, $game_str);
+
+    if(scalar @arr == 1){
+	return "";
+    }
+    return join("\n", splice(@arr, 0, -1))
+}
+
+# printf("%s\n", $ns0);
+# $ns0 = roll_back($ns0);
+# printf("%s\n", $ns0);
+
+$b = LPST->new();
 NTVL->f1($b, $ns0);
 
-$b->shade_all_p2_mvmt();
-$b->disp_board();
+# $b->shade_all_p2_mvmt();
+# $b->disp_board();