diff --git a/kadai4/mukai/README.md b/kadai4/mukai/README.md
new file mode 100644
index 0000000..60a8422
--- /dev/null
+++ b/kadai4/mukai/README.md
@@ -0,0 +1,41 @@
+# 実行例
+```
+ curl -v http://localhost:8080
+* Rebuilt URL to: http://localhost:8080/
+*   Trying ::1...
+* Connected to localhost (::1) port 8080 (#0)
+> GET / HTTP/1.1
+> Host: localhost:8080
+> User-Agent: curl/7.43.0
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Content-Type: application/json; charset=utf-8
+< Date: Wed, 11 Jul 2018 16:57:05 GMT
+< Content-Length: 19
+<
+{"data":"大吉"}
+
+curl -v http://localhost:8080
+* Rebuilt URL to: http://localhost:8080/
+*   Trying ::1...
+* Connected to localhost (::1) port 8080 (#0)
+> GET / HTTP/1.1
+> Host: localhost:8080
+> User-Agent: curl/7.43.0
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Content-Type: application/json; charset=utf-8
+< Date: Wed, 11 Jul 2018 16:57:14 GMT
+< Content-Length: 16
+<
+{"data":"凶"}
+
+```
+
+# 指定日のテスト
+おみくじをひく日時を返却するメソッドを持ったインタフェースをHandlerにもたせる.
+
+本番実装では、実行時の日地を返却するメソッドを持った構造体を渡し、テスト時には任意の日時を返却する構造体を渡すことで、実装を変えずに任意の日付のおみくじ結果を取得できる.
+
diff --git a/kadai4/mukai/handler/dateProvider.go b/kadai4/mukai/handler/dateProvider.go
new file mode 100644
index 0000000..9b14a6a
--- /dev/null
+++ b/kadai4/mukai/handler/dateProvider.go
@@ -0,0 +1,21 @@
+package handler
+
+import "time"
+
+type TimeProvider interface {
+	Time() time.Time
+}
+
+type NowTimeProvider struct { }
+// 実行時の日時を返却する.
+func (p NowTimeProvider) Time() time.Time {
+	return time.Now()
+}
+
+type ArbitraryTimeProvider struct {
+	time time.Time
+}
+// ArbitraryTimeProviderに設定した任意の日時を返却する.
+func (p ArbitraryTimeProvider) Time() time.Time {
+	return p.time
+}
diff --git a/kadai4/mukai/handler/middleWare.go b/kadai4/mukai/handler/middleWare.go
new file mode 100644
index 0000000..546a5c5
--- /dev/null
+++ b/kadai4/mukai/handler/middleWare.go
@@ -0,0 +1,10 @@
+package handler
+
+import "net/http"
+
+func HeaderMiddleWare(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Content-Type", "application/json; charset=utf-8")
+		h.ServeHTTP(w, r)
+	})
+}
diff --git a/kadai4/mukai/handler/omikujiHandler.go b/kadai4/mukai/handler/omikujiHandler.go
new file mode 100644
index 0000000..2375bf0
--- /dev/null
+++ b/kadai4/mukai/handler/omikujiHandler.go
@@ -0,0 +1,41 @@
+package handler
+
+import (
+	"net/http"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"math/rand"
+)
+
+type OmikujiHandler struct {
+	TimeProvider TimeProvider
+}
+func (o OmikujiHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	result := result{Data: o.omikuji()}
+	var buf bytes.Buffer
+	if err := json.NewEncoder(&buf).Encode(result); err != nil {
+		fmt.Fprintln(w, "error")
+	}
+	fmt.Fprintln(w, buf.String())
+}
+
+func (o OmikujiHandler) omikuji() string {
+	time := o.TimeProvider.Time()
+	if time.Month() == 1 && (1 <= time.Day() && time.Day() <= 3) {
+		return "大吉"
+	}
+	i := rand.Intn(4)
+	switch i {
+	case 0: return "大吉"
+	case 1: return "中吉"
+	case 2: return "小吉"
+	case 3: return "凶"
+	default: return "凶"
+	}
+}
+
+type result struct {
+	Data string `json:"data"`
+}
+
diff --git a/kadai4/mukai/handler/omikujiHandler_test.go b/kadai4/mukai/handler/omikujiHandler_test.go
new file mode 100644
index 0000000..40cd015
--- /dev/null
+++ b/kadai4/mukai/handler/omikujiHandler_test.go
@@ -0,0 +1,46 @@
+package handler
+
+import (
+	"net/http/httptest"
+	"testing"
+	"time"
+	"reflect"
+	"encoding/json"
+	"log"
+)
+
+func TestOmikujiHandler(t *testing.T) {
+	type fields struct {
+		month time.Month
+		day int
+	}
+
+	tests := []struct {
+		name   string
+		fields fields
+		want string
+	}{
+		{name:"1/1", fields:fields{month:1, day:1}, want:"大吉"},
+		{name:"1/2", fields:fields{month:1, day:2}, want:"大吉"},
+		{name:"1/3", fields:fields{month:1, day:3}, want:"大吉"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest("GET", "/", nil)
+			loc, _ := time.LoadLocation("Asia/Tokyo")
+			date := time.Date(2018, tt.fields.month, tt.fields.day, 0, 0, 0, 0, loc)
+			OmikujiHandler{TimeProvider: ArbitraryTimeProvider{time: date}}.ServeHTTP(w, r)
+			rw := w.Result()
+			defer rw.Body.Close()
+			decoder := json.NewDecoder(rw.Body)
+			var result result
+			if err := decoder.Decode(&result); err != nil {
+				log.Fatal(err)
+			}
+			if !reflect.DeepEqual(result.Data, tt.want) {
+				t.Errorf("omikujiHandler = %v, want %v", result.Data, tt.want)
+			}
+		})
+	}
+}
diff --git a/kadai4/mukai/main.go b/kadai4/mukai/main.go
new file mode 100644
index 0000000..283b6c3
--- /dev/null
+++ b/kadai4/mukai/main.go
@@ -0,0 +1,17 @@
+package main
+
+import (
+	"dojo2/kadai4/mukai/handler"
+	"math/rand"
+	"net/http"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func main() {
+	http.Handle("/", handler.HeaderMiddleWare(handler.OmikujiHandler{TimeProvider: handler.NowTimeProvider{}}))
+	http.ListenAndServe(":8080", nil)
+}