diff --git a/em-oop/src/Day3Check1.java b/em-oop/src/Day3Check1.java
index 251950e..de6cf95 100644
--- a/em-oop/src/Day3Check1.java
+++ b/em-oop/src/Day3Check1.java
@@ -4,6 +4,10 @@ public class Day3Check1 {
 	public static void main(String[] args) {
 		Circle circle = new Circle(2);
 		circle.showInfo();
+		Rectangle rectangle = new Rectangle(3,4);
+		rectangle.showInfo();
+		
+		Greeting greeting = new JapaneseGreeting();
+		System.out.println(greeting.hello());
 	}
-
 }
diff --git a/em-oop/src/Greeting.java b/em-oop/src/Greeting.java
new file mode 100644
index 0000000..57d8fb6
--- /dev/null
+++ b/em-oop/src/Greeting.java
@@ -0,0 +1,4 @@
+
+public interface Greeting {
+	String hello();
+}
diff --git a/em-oop/src/JapaneseGreeting.java b/em-oop/src/JapaneseGreeting.java
new file mode 100644
index 0000000..5ad3399
--- /dev/null
+++ b/em-oop/src/JapaneseGreeting.java
@@ -0,0 +1,9 @@
+
+public class JapaneseGreeting implements Greeting {
+	@Override
+	public String hello() {
+		String str =("こんにちは");
+		return str;
+	}
+
+}
diff --git a/em-oop/src/Shape.java b/em-oop/src/Shape.java
index baf0a9c..c36c2da 100644
--- a/em-oop/src/Shape.java
+++ b/em-oop/src/Shape.java
@@ -1,13 +1,13 @@
 
-public class Shape {
+public abstract class Shape {
 	private String name;
 	
 	public Shape (String name) {
 		this.name = name;
 	}
-	public double area() {
-		return 0.0;
-	}
+	
+	public abstract double area() ;
+	
 	public void showInfo() {
 		System.out.println(this.name + "の面積は" +this.area() + "です");
 	}