diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/BlueLightRedLight.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/BlueLightRedLight.kt
new file mode 100644
index 0000000..e58ce33
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/BlueLightRedLight.kt
@@ -0,0 +1,12 @@
+package com.gof.pattern.strategy.after
+
+class BlueLightRedLight {
+
+    fun blueLight(speed: Speed) {
+        speed.blueLight()
+    }
+
+    fun redLight(speed: Speed) {
+        speed.redLight()
+    }
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Client.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Client.kt
new file mode 100644
index 0000000..075d986
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Client.kt
@@ -0,0 +1,19 @@
+package com.gof.pattern.strategy.after
+
+class Client {
+}
+
+fun main() {
+    val game = BlueLightRedLight()
+    game.blueLight(Normal())
+    game.redLight(Faster())
+    game.blueLight(object : Speed {
+        override fun blueLight() {
+            println("blue light")
+        }
+
+        override fun redLight() {
+            println("red light")
+        }
+    })
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Faster.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Faster.kt
new file mode 100644
index 0000000..8a33429
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Faster.kt
@@ -0,0 +1,11 @@
+package com.gof.pattern.strategy.after
+
+class Faster : Speed {
+    override fun blueLight() {
+        println("무궁화꽃이")
+    }
+
+    override fun redLight() {
+        println("피었습니다.")
+    }
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Normal.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Normal.kt
new file mode 100644
index 0000000..34a3aae
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Normal.kt
@@ -0,0 +1,11 @@
+package com.gof.pattern.strategy.after
+
+class Normal : Speed {
+    override fun blueLight() {
+        println("무 궁 화   꽃  이")
+    }
+
+    override fun redLight() {
+        println("피 었 습 니 다.")
+    }
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Speed.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Speed.kt
new file mode 100644
index 0000000..dad4590
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/after/Speed.kt
@@ -0,0 +1,7 @@
+package com.gof.pattern.strategy.after
+
+interface Speed {
+
+    fun blueLight()
+    fun redLight()
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/BlueLightRedLight.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/BlueLightRedLight.kt
new file mode 100644
index 0000000..c8f40dc
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/BlueLightRedLight.kt
@@ -0,0 +1,20 @@
+package com.gof.pattern.strategy.before
+
+class BlueLightRedLight(private val speed: Int) {
+
+    fun blueLight() {
+        when (speed) {
+            1 -> println("무 궁 화   꽃  이")
+            2 -> println("무궁화꽃이")
+            else -> println("무광꼬치")
+        }
+    }
+
+    fun redLight() {
+        when (speed) {
+            1 -> println("피 었 습 니 다.")
+            2 -> println("피었습니다.")
+            3 -> println("피었슴다")
+        }
+    }
+}
\ No newline at end of file
diff --git a/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/Client.kt b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/Client.kt
new file mode 100644
index 0000000..58b3500
--- /dev/null
+++ b/ria/gof/src/main/kotlin/com/gof/pattern/strategy/before/Client.kt
@@ -0,0 +1,10 @@
+package com.gof.pattern.strategy.before
+
+class Client {
+}
+
+fun main() {
+    val blueLightRedLight = BlueLightRedLight(3)
+    blueLightRedLight.blueLight()
+    blueLightRedLight.redLight()
+}
\ No newline at end of file
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/BlueLightRedLight.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/BlueLightRedLight.java
new file mode 100644
index 0000000..2c3d6e7
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/BlueLightRedLight.java
@@ -0,0 +1,13 @@
+package com.gof.pattern.strategy.after;
+
+// Context Class
+public class BlueLightRedLight {
+
+    public void blueLight(Speed speed) {
+        speed.blueLight();
+    }
+
+    public void redLight(Speed speed) {
+        speed.redLight();
+    }
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Client.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Client.java
new file mode 100644
index 0000000..cdcbd55
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Client.java
@@ -0,0 +1,21 @@
+package com.gof.pattern.strategy.after;
+
+public class Client {
+
+    public static void main(String[] args) {
+        BlueLightRedLight game = new BlueLightRedLight();
+        game.blueLight(new Normal());
+        game.redLight(new Faster());
+        game.blueLight(new Speed() {
+            @Override
+            public void blueLight() {
+                System.out.println("blue light");
+            }
+
+            @Override
+            public void redLight() {
+                System.out.println("red light");
+            }
+        });
+    }
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Faster.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Faster.java
new file mode 100644
index 0000000..cc3ffe9
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Faster.java
@@ -0,0 +1,13 @@
+package com.gof.pattern.strategy.after;
+
+public class Faster implements Speed {
+    @Override
+    public void blueLight() {
+        System.out.println("무궁화꽃이");
+    }
+
+    @Override
+    public void redLight() {
+        System.out.println("피었습니다.");
+    }
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Normal.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Normal.java
new file mode 100644
index 0000000..8069315
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Normal.java
@@ -0,0 +1,13 @@
+package com.gof.pattern.strategy.after;
+
+public class Normal implements Speed {
+    @Override
+    public void blueLight() {
+        System.out.println("무 궁 화     꽃   이");
+    }
+
+    @Override
+    public void redLight() {
+        System.out.println("피 었 습 니  다.");
+    }
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Speed.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Speed.java
new file mode 100644
index 0000000..e472703
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/after/Speed.java
@@ -0,0 +1,8 @@
+package com.gof.pattern.strategy.after;
+
+public interface Speed {
+
+    void blueLight();
+
+    void redLight();
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/BlueLightRedLight.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/BlueLightRedLight.java
new file mode 100644
index 0000000..2f36e80
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/BlueLightRedLight.java
@@ -0,0 +1,30 @@
+package com.gof.pattern.strategy.before;
+
+public class BlueLightRedLight {
+
+    private int speed;
+
+    public BlueLightRedLight(int speed) {
+        this.speed = speed;
+    }
+
+    public void blueLight() {
+        if (speed == 1) {
+            System.out.println("무 궁 화     꽃   이");
+        } else if (speed == 2) {
+            System.out.println("무궁화꽃이");
+        } else {
+            System.out.println("무광꼬치");
+        }
+    }
+
+    public void redLight() {
+        if (speed == 1) {
+            System.out.println("피 었 습 니  다.");
+        } else if (speed == 2) {
+            System.out.println("피었습니다.");
+        } else {
+            System.out.println("피었슴다.");
+        }
+    }
+}
diff --git a/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/Client.java b/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/Client.java
new file mode 100644
index 0000000..f2ca930
--- /dev/null
+++ b/ria/java/gof/src/main/java/com/gof/pattern/strategy/before/Client.java
@@ -0,0 +1,10 @@
+package com.gof.pattern.strategy.before;
+
+public class Client {
+
+    public static void main(String[] args) {
+        BlueLightRedLight blueLightRedLight = new BlueLightRedLight(3);
+        blueLightRedLight.blueLight();
+        blueLightRedLight.redLight();
+    }
+}