diff --git a/lib/bcdice/game_system/SwordWorld.rb b/lib/bcdice/game_system/SwordWorld.rb
index d48877300..deeaf21d1 100644
--- a/lib/bcdice/game_system/SwordWorld.rb
+++ b/lib/bcdice/game_system/SwordWorld.rb
@@ -334,6 +334,11 @@ def getResultText(rating_total, command, diceResults, diceResultTotals,
             if command.modifier_after_half != 0
               text += Format.modifier(command.modifier_after_half)
             end
+          elsif command.one_and_a_half
+            text = "(#{text})*1.5"
+            if command.modifier_after_one_and_a_half != 0
+              text += Format.modifier(command.modifier_after_one_and_a_half)
+            end
           end
           sequence.push(text)
         elsif command.half
@@ -342,6 +347,12 @@ def getResultText(rating_total, command, diceResults, diceResultTotals,
             text += Format.modifier(command.modifier_after_half)
           end
           sequence.push(text)
+        elsif command.one_and_a_half
+          text = "#{rateResults.first}*1.5"
+          if command.modifier_after_one_and_a_half != 0
+            text += Format.modifier(command.modifier_after_one_and_a_half)
+          end
+          sequence.push(text)
         end
 
         if round > 1
@@ -355,6 +366,11 @@ def getResultText(rating_total, command, diceResults, diceResultTotals,
           if command.modifier_after_half != 0
             total += command.modifier_after_half
           end
+        elsif command.one_and_a_half
+          total = (total * 1.5).ceil
+          if command.modifier_after_one_and_a_half != 0
+            total += command.modifier_after_one_and_a_half
+          end
         end
 
         total_text = total.to_s
diff --git a/lib/bcdice/game_system/SwordWorld2_5.rb b/lib/bcdice/game_system/SwordWorld2_5.rb
index 45c68dc1f..4fc04ede9 100644
--- a/lib/bcdice/game_system/SwordWorld2_5.rb
+++ b/lib/bcdice/game_system/SwordWorld2_5.rb
@@ -39,6 +39,13 @@ class SwordWorld2_5 < SwordWorld2_0
         　クリティカル値を指定しない場合、クリティカルなしと扱われます。
         　例）HK20　　K20h　　HK10-5@9　　K10-5@9H　　K20gfH　　K20+8H+2　　K20+8H+(1+1)
 
+        ・レーティング表の1.5倍 (OHKx, KxOH+N)
+        　レーティング表の先頭または末尾に"OH"をつけると、レーティング表を振って最終結果を1.5倍します。
+        　末尾につけた場合、直後に修正ををつけることで、1.5倍後の加減算を行うことができます。
+        　この際、複数の項による修正にはカッコで囲うことが必要です（カッコがないとパースに失敗します）
+        　クリティカル値を指定しない場合、クリティカルなしと扱われます。
+        　例）OHK20　　K20oh　　OHK10-5@9　　K20+8OH+2　　K20+8OH+(1+1)
+
         ・ダイス目の修正（運命変転やクリティカルレイ用）
         　末尾に「$修正値」でダイス目に修正がかかります。
         　$＋１と修正表記ならダイス目に＋修正、＄９のように固定値ならダイス目をその出目に差し替え。
@@ -82,7 +89,7 @@ class SwordWorld2_5 < SwordWorld2_0
         　アビスカース表を出すことができます。
       INFO_MESSAGE_TEXT
 
-      register_prefix('H?K', 'Gr', '2D6?@\d+', 'FT', 'TT', 'Dru', 'ABT')
+      register_prefix('H?K', 'OHK', 'Gr', '2D6?@\d+', 'FT', 'TT', 'Dru', 'ABT')
 
       def eval_game_system_specific_command(command)
         case command
diff --git a/lib/bcdice/game_system/sword_world/rating_options.rb b/lib/bcdice/game_system/sword_world/rating_options.rb
index f6e85388b..431f7749e 100644
--- a/lib/bcdice/game_system/sword_world/rating_options.rb
+++ b/lib/bcdice/game_system/sword_world/rating_options.rb
@@ -34,6 +34,9 @@ class RatingOptions
         # @return [Integer, nil]
         attr_accessor :modifier_after_half
 
+        # @return [Integer, nil]
+        attr_accessor :modifier_after_one_and_a_half
+
         def settable_first_roll_adjust_option?
           return first_modify.nil? && first_to.nil?
         end
diff --git a/lib/bcdice/game_system/sword_world/rating_parsed.rb b/lib/bcdice/game_system/sword_world/rating_parsed.rb
index c783acc4e..4d7109114 100644
--- a/lib/bcdice/game_system/sword_world/rating_parsed.rb
+++ b/lib/bcdice/game_system/sword_world/rating_parsed.rb
@@ -37,6 +37,9 @@ class RatingParsed
         # @return [Integer, nil]
         attr_accessor :modifier_after_half
 
+        # @return [Integer, nil]
+        attr_accessor :modifier_after_one_and_a_half
+
         def initialize(rate, modifier)
           @rate = rate
           @modifier = modifier
@@ -49,6 +52,7 @@ def initialize(rate, modifier)
           @semi_fixed_val = 0
           @tmp_fixed_val = 0
           @modifier_after_half = nil
+          @modifier_after_one_and_a_half = nil
         end
 
         # @return [Boolean]
@@ -56,6 +60,11 @@ def half
           return !@modifier_after_half.nil?
         end
 
+        # @return [Boolean]
+        def one_and_a_half
+          return !@modifier_after_one_and_a_half.nil?
+        end
+
         # @return [Integer]
         def min_critical
           if @semi_fixed_val <= 1
diff --git a/lib/bcdice/game_system/sword_world/rating_parser.y b/lib/bcdice/game_system/sword_world/rating_parser.y
index 9918706e6..83aa2fbe6 100644
--- a/lib/bcdice/game_system/sword_world/rating_parser.y
+++ b/lib/bcdice/game_system/sword_world/rating_parser.y
@@ -1,5 +1,5 @@
 class RatingParser
-  token NUMBER K R H G F S T PLUS MINUS ASTERISK SLASH PARENL PARENR BRACKETL BRACKETR AT SHARP DOLLAR
+  token NUMBER K R H O G F S T PLUS MINUS ASTERISK SLASH PARENL PARENR BRACKETL BRACKETR AT SHARP DOLLAR
 
   expect 4
 
@@ -13,10 +13,19 @@ class RatingParser
         | H rate option
         {
           _, rate, option = val
+          raise ParseError if option.modifier_after_one_and_a_half
           option.modifier_after_half ||= Arithmetic::Node::Number.new(0)
           modifier = option.modifier || Arithmetic::Node::Number.new(0)
           result = parsed(rate, modifier.eval(@round_type), option)
         }
+        | O H rate option
+        {
+          _, _, rate, option = val
+          raise ParseError if option.modifier_after_half
+          option.modifier_after_one_and_a_half ||= Arithmetic::Node::Number.new(0)
+          modifier = option.modifier || Arithmetic::Node::Number.new(0)
+          result = parsed(rate, modifier.eval(@round_type), option)
+        }
 
 
     rate: K NUMBER
@@ -90,6 +99,22 @@ class RatingParser
             option.modifier_after_half = term
             result = option
           }
+          | option O H
+          {
+            option, _ = val
+            raise ParseError if option.modifier_after_one_and_a_half
+
+            option.modifier_after_one_and_a_half = Arithmetic::Node::Number.new(0)
+            result = option
+          }
+          | option O H unary
+          {
+            option, _, term = val
+            raise ParseError if option.modifier_after_one_and_a_half
+
+            option.modifier_after_one_and_a_half = term
+            result = option
+          }
           | option R unary
           {
             option, _, term = val
@@ -214,7 +239,8 @@ def parsed(rate, modifier, option)
     p.semi_fixed_val = option.semi_fixed_val&.clamp(1, 6) || 0
     p.tmp_fixed_val = option.tmp_fixed_val&.clamp(1, 6) || 0
     p.modifier_after_half = option.modifier_after_half&.eval(@round_type)
-    p.critical = option.critical&.eval(@round_type)&.clamp(0, 13) || (p.half ? 13 : 10)
+    p.modifier_after_one_and_a_half = option.modifier_after_one_and_a_half&.eval(@round_type)
+    p.critical = option.critical&.eval(@round_type)&.clamp(0, 13) || (p.half || p.one_and_a_half ? 13 : 10)
   end
 end
 
diff --git a/test/data/SwordWorld2_5.toml b/test/data/SwordWorld2_5.toml
index 952c9593e..4061f164a 100644
--- a/test/data/SwordWorld2_5.toml
+++ b/test/data/SwordWorld2_5.toml
@@ -416,6 +416,95 @@ rands = [
   { sides = 6, value = 1 },
 ]
 
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "OHk10 OHKのクリティカル値は13"
+output = "KeyNo.10 ＞ 2D:[6,6]=12 ＞ 7*1.5 ＞ 11"
+rands = [
+  { sides = 6, value = 6 },
+  { sides = 6, value = 6 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "k10oh"
+output = "KeyNo.10 ＞ 2D:[6,6]=12 ＞ 7*1.5 ＞ 11"
+rands = [
+  { sides = 6, value = 6 },
+  { sides = 6, value = 6 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "ohk10oh"
+output = "KeyNo.10 ＞ 2D:[6,6]=12 ＞ 7*1.5 ＞ 11"
+rands = [
+  { sides = 6, value = 6 },
+  { sides = 6, value = 6 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "ohk10[9]+10"
+output = "KeyNo.10c[9]+10 ＞ 2D:[5,3]=8 ＞ (4+10)*1.5 ＞ 21"
+rands = [
+  { sides = 6, value = 5 },
+  { sides = 6, value = 3 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "ohk10[9]+10 切り上げ"
+output = "KeyNo.10c[9]+10 ＞ 2D:[2,4]=6 ＞ (3+10)*1.5 ＞ 20"
+rands = [
+  { sides = 6, value = 2 },
+  { sides = 6, value = 4 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "OHK20+6@4"
+output = "KeyNo.20c[4]+6 ＞ 2D:[4,3 2,5 2,6 1,1]=7,7,8,2 ＞ (5,5,6,**+6)*1.5 ＞ 3回転 ＞ 33"
+critical = true
+rands = [
+  { sides = 6, value = 4 },
+  { sides = 6, value = 3 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 5 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 6 },
+  { sides = 6, value = 1 },
+  { sides = 6, value = 1 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "K20+6@4oh"
+output = "KeyNo.20c[4]+6 ＞ 2D:[4,3 2,5 2,6 1,1]=7,7,8,2 ＞ (5,5,6,**+6)*1.5 ＞ 3回転 ＞ 33"
+critical = true
+rands = [
+  { sides = 6, value = 4 },
+  { sides = 6, value = 3 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 5 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 6 },
+  { sides = 6, value = 1 },
+  { sides = 6, value = 1 },
+]
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "hk10oh"
+output = ""
+rands = []
+
+[[ test ]]
+game_system = "SwordWorld2.5"
+input = "ohk10h"
+output = ""
+rands = []
+
 [[ test ]]
 game_system = "SwordWorld2.5"
 input = "k20sf4 sf通常時"