diff -ur kpcal-2.0-orig/kpcal.c kpcal-2.0/kpcal.c
--- kpcal-2.0-orig/kpcal.c	1990-01-30 19:19:40.000000000 +0900
+++ kpcal-2.0/kpcal.c	2003-04-21 22:07:00.000000000 +0900
@@ -169,6 +169,7 @@
    */
   PRT("/year %d def\n", year);
   PRT("/month %d def\n", m);
+  PRT("defineholiday\n");
   PRT("printmonth\n\n");
 
   /*
diff -ur kpcal-2.0-orig/kpcal_header.h kpcal-2.0/kpcal_header.h
--- kpcal-2.0-orig/kpcal_header.h	1990-01-30 19:19:40.000000000 +0900
+++ kpcal-2.0/kpcal_header.h	2004-05-18 19:57:49.000000000 +0900
@@ -46,21 +46,25 @@
   "/month_names [ (January) (February) (March) (April) (May) (June) (July)",
   "               (August) (September) (October) (November) (December) ] def",
   "",
-  "/holidays [",
-  " []        % NONE",
-  " [ 1 15 ]  % January",
-  " [ 11 ]    % Feburay",
-  " [ 21 ]    % March",
-  " [ 29 ]    % April",
-  " [ 3 4 5 ] % March",
-  " []        % June",
-  " []        % July",
-  " []        % Auguest",
-  " [ 15 23 ] % September",
-  " [ 10 ]    % October",
-  " [ 3 23 ]  % November",
-  " [ 23 ]    % December",
-  "] def",
+  "/defineholiday {",
+  "  /holidays [",
+  "   []        % NONE",
+  "   [ 1 year 2000 ge { 15 year 1 1 startday dup 1 le { 6 add sub } { 1 sub sub } ifelse } { 15 } ifelse ]  % January",
+  "   [ 11 ]    % February",
+  "   [ year 1980 ge year 2099 le and { 20.8431 0.242194 year 1980 sub mul year 1980 sub 4 div cvi sub add cvi } { 21 } ifelse]    % March",
+  "   [ 29 ]    % April",
+  "   [ 3 4 5 ] % May",
+  "   []        % June",
+  "   [ year 2003 ge { 22 year 7 1 startday dup 1 le { 6 add sub } { 1 sub sub } ifelse } { 20 } ifelse ]        % July",
+  "   []        % Auguest",
+  "   [ year 2003 ge { 22 year 9 1 startday dup 1 le { 6 add sub } { 1 sub sub } ifelse } { 15 } ifelse",
+  "     year 1980 ge year 2099 le and { 23.2488 0.242194 year 1980 sub mul year 1980 sub 4 div cvi sub add cvi } { 23 } ifelse",
+  "     4 { 1 index } repeat sub abs 2 eq { add 2 div cvi } { pop pop } ifelse ] % September",
+  "   [ year 2000 ge { 10 year 10 1 startday dup 1 le { 1 add sub } { 6 exch sub add } ifelse } { 10 } ifelse ]    % October",
+  "   [ 3 23 ]  % November",
+  "   [ 23 ]    % December",
+  "  ] def",
+  "} def",
   "",
   "/daymap 32 array def",
   "",
@@ -90,7 +94,7 @@
   "",
   "/drawnums {       % place day numbers on calendar",
   "  dayfont findfont 30 scalefont setfont",
-  "  /start startday def",
+  "  /start year month 1 startday def",
   "  /days ndays def",
   "  start 100 mul 5 add 10 rmoveto",
   "  submonth 0 eq {",
@@ -98,18 +102,21 @@
   "      daymap exch dup",
   "      start add 7 mod",
   "      dup 1 eq {",
-  "        pop 2",
+  "        pop 2 % Sunday",
   "      }",
   "      {",
-  "        0 eq { 1 } { 0 } ifelse",
+  "        0 eq { 1 } { 0 } ifelse % Saturday / Weekday",
   "      } ifelse",
   "      put",
   "    } for",
   "    holidays month get {",
-  "      dup daymap exch get 2 eq {",
-  "        1 add",
+  "      /tmpday exch def",
+  "      daymap tmpday get 2 eq",
+  "      daymap tmpday 1 sub get 2 ne",
+  "      daymap tmpday 1 add get 2 ne and and { % substitute holiday",
+  "        /tmpday tmpday 1 add def",
   "      } { } ifelse",
-  "      daymap exch 2 put",
+  "      daymap tmpday 2 put % holiday",
   "    } forall",
   "  }",
   "  {",
@@ -144,7 +151,7 @@
   "} def",
   "",
   "/drawfill {         % place fill squares on calendar",
-  "  /start startday def",
+  "  /start year month 1 startday def",
   "  /days ndays def",
   "  0 35 rmoveto",
   "  1.0 setlinewidth",
@@ -190,7 +197,7 @@
   "/isleap {                    % is this a leap year?",
   "  year 4 mod 0 eq            % multiple of 4",
   "  year 100 mod 0 ne          % not century",
-  "  year 1000 mod 0 eq or and  % unless it's a millenia",
+  "  year 400 mod 0 eq or and",
   "} def",
   "",
   "/days_month [ 31 28 31 30 31 30 31 31 30 31 30 31 ] def",
@@ -205,24 +212,27 @@
   "} def",
   "",
   "/startday {    % starting day-of-week for this month",
-  "  /off year 2000 sub def     % offset from start of epoch",
-  "  off",
-  "  off 4 idiv add             % number of leap years",
-  "  off 100 idiv sub           % number of centuries",
-  "  off 1000 idiv add          % number of millenia",
-  "  6 add 7 mod 7 add          % offset from Jan 1 2000",
-  "  /off exch def",
-  "  1 1 month 1 sub {",
-  "    /idx exch def",
-  "    days_month idx 1 sub get",
-  "    idx 2 eq",
-  "    isleap and",
-  "    {",
-  "      1 add",
-  "    } if",
-  "    /off exch off add def",
-  "  } for",
-  "  off 7 mod                 % 0--Sunday, 1--monday, etc.",
+  "  /_d exch def  % day",
+  "  /_m exch def  % month",
+  "  /_y exch def  % year",
+  "  _m 2 le {",
+  "    /mm _m 12 add def /yy _y 1 sub def",
+  "  } {",
+  "    /mm _m def /yy _y def",
+  "  } ifelse",
+  "  /yy1 yy 100 div truncate cvi def",
+  "  /yy2 yy yy1 100 mul sub cvi def",
+  "  /off yy2 yy2 4 idiv add",
+  "  yy1 4 idiv add",
+  "  26 mm 1 add mul 10 idiv add",
+  "  2 yy1 mul sub",
+  "  _d add",
+  "  7 mod",
+  "  def",
+  "  off 0 le {",
+  "    /off off 7 add def",
+  "  } if",
+  "  off 1 sub   % 0--Sunday, 1--monday, etc.",
   "} def",
   "",
   "/center {                   % center string in given width",
@@ -252,7 +262,7 @@
   "  /CompTextFont findfont 6 scalefont setfont",
   "  /mytext exch def",
   "  /myday exch def",
-  "  startday myday 1 sub add dup 7 mod 100 mul 5 add % gives column",
+  "  year month 1 startday myday 1 sub add dup 7 mod 100 mul 5 add % gives column",
   "  exch 7 idiv -80 mul % gives row",
   "  dup /ypos exch def moveto",
   "  /LM currentpoint pop def /RM LM 95 add def",