diff --git a/src/main/java/info/istlab/dp/dp2/DecoratorTest.java b/src/main/java/info/istlab/dp/dp2/DecoratorTest.java
new file mode 100644
index 0000000..67ad0d3
--- /dev/null
+++ b/src/main/java/info/istlab/dp/dp2/DecoratorTest.java
@@ -0,0 +1,96 @@
+package info.istlab.dp.dp2;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+
+/**
+ * 誕生日：通常は西暦で管理しており、年齢などを出力するが、
+ * 必要に応じて和暦で表示する。
+ */
+public class DecoratorTest {
+    public static void main(String[] args) {
+        ArrayList<LocalDate> chkDays = new ArrayList<LocalDate>();
+        chkDays.add(LocalDate.now());
+        chkDays.add(LocalDate.of(2023, 5, 2));
+        chkDays.add(LocalDate.of(2019, 5, 1));
+        chkDays.add(LocalDate.of(2019, 4, 30));
+        chkDays.add(LocalDate.of(1989, 1, 8));
+        chkDays.add(LocalDate.of(1989, 1, 7));
+
+        for (LocalDate ld : chkDays) {
+            Wareki wareki = new Wareki(ld);
+            System.out.println(wareki.toString());
+            System.out.println("-----");
+        }
+    }
+}
+
+/**
+ * LocalDate を装飾(Decorate)する和暦クラス
+ * つかいかたの例：
+ * Wareki wareki = new Wareki( LocalDate.now() );
+ * System.out.println(wareki.toString());
+ * 
+ * または： System.out.println( Wareki.localDate2Wareki( LocalDate.now() ) );
+ */
+class Wareki {
+    LocalDate ld;
+
+    public Wareki(LocalDate _ld) {
+        ld = _ld;
+    }
+
+    public String toString() {
+        return localDate2Wareki(ld);
+    }
+
+    /**
+     * LocalDate から和暦を返す
+     * @param d LocalDate
+     * @return 和暦
+     */
+    public static String localDate2Wareki(LocalDate d) {
+        int month = d.getMonthValue();
+        int day = d.getDayOfMonth();
+        return String.format("%s/%02d/%02d", getNengo(d), month, day);
+    }
+
+    /**
+     * 年号アルファベット＋年 を返す
+     * 
+     * @return 年号アルファベット＋年
+     */
+    public static String getNengo(LocalDate localDate) {
+        String[] nengoArray = { "M", "T", "S", "H", "R" }; // Meiji,Taisho,Showa,Heisei,Reiwa
+        int[] fromYear = { 1868, 1912, 1926, 1989, 2019 };
+        int[] fromMonth = { 1, 7, 12, 1, 5 };
+        int[] fromDay = { 25, 30, 25, 8, 1 };
+
+        int year = localDate.getYear();
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy/MM/dd");
+
+        String ymd = formatter.format(localDate); // 形式：YYYY/MM/DD (例: 1999/10/22)
+        String nengo = null;
+        int nengoYear = 0;
+        for (int i = nengoArray.length - 1; i > 0; i--) {
+            String fromYMD = new BirthDay(fromYear[i], fromMonth[i], fromDay[i]).toString();
+            // System.out.print(" >> check "+fromYMD+" <= "+ymd);
+            if (fromYMD.compareTo(ymd) <= 0) { // YYYY/MM/DD文字列の大小関係でチェックしている
+                // System.out.println(" OK");
+                nengo = nengoArray[i];
+                nengoYear = year - fromYear[i] + 1;
+                break;
+            } else {
+                // System.out.println(" X");
+            }
+        }
+        if (nengo == null) {
+            nengo = "E";
+            nengoYear = year - 1603 + 1;
+        }
+        return String.format("%s%02d", nengo, nengoYear); // ex. R05 H30
+    }
+
+}
+