diff --git a/lib/bcdice/game_system.rb b/lib/bcdice/game_system.rb
index 9bfd7fe1e..69136c40c 100644
--- a/lib/bcdice/game_system.rb
+++ b/lib/bcdice/game_system.rb
@@ -171,6 +171,7 @@
 require "bcdice/game_system/SamsaraBallad"
 require "bcdice/game_system/Satasupe"
 require "bcdice/game_system/ScreamHighSchool"
+require "bcdice/game_system/Sengensyou"
 require "bcdice/game_system/SevenFortressMobius"
 require "bcdice/game_system/ShadowRun"
 require "bcdice/game_system/ShadowRun4"
diff --git a/lib/bcdice/game_system/Sengensyou.rb b/lib/bcdice/game_system/Sengensyou.rb
new file mode 100644
index 000000000..365b0435c
--- /dev/null
+++ b/lib/bcdice/game_system/Sengensyou.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module BCDice
+  module GameSystem
+    class Sengensyou < Base
+      # ゲームシステムの識別子
+      ID = 'Sengensyou'
+
+      # ゲームシステム名
+      NAME = '千幻抄'
+
+      # ゲームシステム名の読みがな
+      SORT_KEY = 'せんけんしよう'
+
+      # ダイスボットの使い方
+      HELP_MESSAGE = <<~INFO_MESSAGE_TEXT
+        ・SGS　命中判定・回避判定
+      INFO_MESSAGE_TEXT
+
+      register_prefix('SGS')
+
+      def eval_game_system_specific_command(command)
+        # 命中判定・回避判定
+        parser = Command::Parser.new('SGS', round_type: @round_type).restrict_cmp_op_to(nil)
+        command = parser.parse(command)
+
+        unless command
+          return nil
+        end
+
+        dice_list = @randomizer.roll_barabara(3, 6)
+        dice_total = dice_list.sum()
+        is_critical = dice_total >= 16
+        is_fumble = dice_total <= 5
+        additional_text =
+          if is_critical
+            "クリティカル"
+          elsif is_fumble
+            "ファンブル"
+          end
+        modify_text = "#{dice_total}#{Format.modifier(command.modify_number)}" if command.modify_number != 0
+        sequence = [
+          "(3D6#{Format.modifier(command.modify_number)})",
+          "#{dice_total}[#{dice_list.join(',')}]",
+          modify_text,
+          (dice_total + command.modify_number).to_s,
+          additional_text,
+        ].compact
+
+        result = Result.new.tap do |r|
+          r.text = sequence.join(" ＞ ")
+          r.critical = is_critical
+          r.fumble = is_fumble
+        end
+        return result
+      end
+    end
+  end
+end
diff --git a/test/data/Sengensyou.toml b/test/data/Sengensyou.toml
new file mode 100644
index 000000000..b9ddc4949
--- /dev/null
+++ b/test/data/Sengensyou.toml
@@ -0,0 +1,69 @@
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS"
+output = "(3D6) ＞ 8[4,1,3] ＞ 8"
+rands = [
+  { sides = 6, value = 4 },
+  { sides = 6, value = 1 },
+  { sides = 6, value = 3 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS"
+output = "(3D6) ＞ 16[5,5,6] ＞ 16 ＞ クリティカル"
+critical = true
+rands = [
+  { sides = 6, value = 5 },
+  { sides = 6, value = 5 },
+  { sides = 6, value = 6 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS"
+output = "(3D6) ＞ 5[1,2,2] ＞ 5 ＞ ファンブル"
+fumble = true
+rands = [
+  { sides = 6, value = 1 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 2 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS+4+6"
+output = "(3D6+10) ＞ 8[4,1,3] ＞ 8+10 ＞ 18"
+rands = [
+  { sides = 6, value = 4 },
+  { sides = 6, value = 1 },
+  { sides = 6, value = 3 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS+4+6"
+output = "(3D6+10) ＞ 16[5,5,6] ＞ 16+10 ＞ 26 ＞ クリティカル"
+critical = true
+rands = [
+  { sides = 6, value = 5 },
+  { sides = 6, value = 5 },
+  { sides = 6, value = 6 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS+4+6"
+output = "(3D6+10) ＞ 5[1,2,2] ＞ 5+10 ＞ 15 ＞ ファンブル"
+fumble = true
+rands = [
+  { sides = 6, value = 1 },
+  { sides = 6, value = 2 },
+  { sides = 6, value = 2 },
+]
+
+[[ test ]]
+game_system = "Sengensyou"
+input = "SGS>=5"
+output = ""
+rands = []