diff --git a/kadai4/nKumaya/README.md b/kadai4/nKumaya/README.md
new file mode 100644
index 0000000..593d6ae
--- /dev/null
+++ b/kadai4/nKumaya/README.md
@@ -0,0 +1,13 @@
+# 課題4 おみくじAPIを作ってみよう
+
+JSON形式でおみくじの結果を返す  
+正月（1/1-1/3）だけ大吉にする  
+ハンドラのテストを書いてみる  
+
+## 実行方法
+
+```
+go run main.go
+curl http://localhost:8080
+{"date":"2018-09-18T14:00:25.062023813+09:00","result":"末吉"}
+```
diff --git a/kadai4/nKumaya/main.go b/kadai4/nKumaya/main.go
new file mode 100644
index 0000000..0c2948f
--- /dev/null
+++ b/kadai4/nKumaya/main.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"math/rand"
+	"net/http"
+	"time"
+)
+
+var fortunes = []string{"大吉", "吉", "中吉", "小吉", "末吉", "凶", "大凶"}
+
+type Omikuji struct {
+	Date   time.Time `json:"date"`
+	Result string    `json:"result"`
+}
+
+func NewOmikuji(date time.Time) *Omikuji {
+	o := Omikuji{Date: date}
+	return &o
+}
+
+type Adapter func(http.Handler) http.Handler
+
+func Adapt(h http.Handler, adapters ...Adapter) http.Handler {
+	for _, adapter := range adapters {
+		h = adapter(h)
+	}
+	return h
+}
+
+func SetHeader() Adapter {
+	return func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json; charset=utf-8")
+			h.ServeHTTP(w, r)
+		})
+	}
+}
+
+func (o *Omikuji) handle(w http.ResponseWriter, r *http.Request) {
+	if o.Date.Month() == 1 && (o.Date.Day() >= 1 && o.Date.Day() <= 3) {
+		o.Result = "大吉"
+	} else {
+		o.Result = fortunes[rand.Int()%len(fortunes)]
+	}
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(o); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Fprintf(w, buf.String())
+}
+
+func main() {
+	o := NewOmikuji(time.Now())
+	handler := http.HandlerFunc(o.handle)
+	http.Handle("/", Adapt(handler, SetHeader()))
+	http.ListenAndServe(":8080", nil)
+}
diff --git a/kadai4/nKumaya/main_test.go b/kadai4/nKumaya/main_test.go
new file mode 100644
index 0000000..31e17b9
--- /dev/null
+++ b/kadai4/nKumaya/main_test.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+func TestHandler(t *testing.T) {
+	t.Helper()
+	dateSet := []time.Time{
+		time.Date(2019, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(2019, 1, 3, 23, 59, 59, 0, time.Local),
+		time.Now(),
+	}
+	omikujis := make([]*Omikuji, 3)
+	for i, v := range dateSet {
+		omikujis[i] = NewOmikuji(v)
+	}
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest("GET", "/", nil)
+	N := 100
+	daikichiCount := 0
+	t.Run("1/1 test", func(t *testing.T) {
+		for i := 0; i < N; i++ {
+			omikujis[0].handle(w, r)
+			if omikujis[0].Result == "大吉" {
+				daikichiCount++
+			}
+		}
+		if daikichiCount != N {
+			t.Errorf("1/1 daikichiCount: %d\n", daikichiCount)
+		}
+		daikichiCount = 0
+	})
+
+	t.Run("1/3 test", func(t *testing.T) {
+		for i := 0; i < N; i++ {
+			omikujis[1].handle(w, r)
+			if omikujis[1].Result == "大吉" {
+				daikichiCount++
+			}
+		}
+		if daikichiCount != N {
+			t.Errorf("1/3 daikichiCount: %d\n", daikichiCount)
+		}
+		daikichiCount = 0
+	})
+
+	t.Run("normal day test", func(t *testing.T) {
+		for i := 0; i < N; i++ {
+			omikujis[2].handle(w, r)
+			if omikujis[2].Result == "大吉" {
+				daikichiCount++
+			}
+		}
+		if daikichiCount == N {
+			t.Errorf("daikichiCount: %d\n", daikichiCount)
+		}
+	})
+
+}