diff --git a/kadai4/tokunaga/main.go b/kadai4/tokunaga/main.go
new file mode 100644
index 0000000..497e34b
--- /dev/null
+++ b/kadai4/tokunaga/main.go
@@ -0,0 +1,41 @@
+// handler は、 HTTP リクエストの情報を返します。
+package main
+
+import (
+	crand "crypto/rand"
+	"log"
+	"math"
+	"math/big"
+	"math/rand"
+	"net/http"
+	"time"
+)
+
+func init() {
+	if err := serRandSeed(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func serRandSeed() error {
+	seed, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
+	rand.Seed(seed.Int64())
+	return err
+}
+
+type timeWrapper struct{}
+type randWrapper struct{}
+
+func (t timeWrapper) Now() time.Time {
+	return time.Now()
+}
+
+func (r randWrapper) Intn(n int) int {
+	return rand.Intn(n)
+}
+
+func main() {
+	omikuji := omikuji{nower: timeWrapper{}, intner: randWrapper{}}
+	http.HandleFunc("/omikuji", omikuji.open)
+	log.Fatal(http.ListenAndServe("localhost:8080", nil))
+}
diff --git a/kadai4/tokunaga/omikuji.go b/kadai4/tokunaga/omikuji.go
new file mode 100644
index 0000000..5025c81
--- /dev/null
+++ b/kadai4/tokunaga/omikuji.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+)
+
+const daikiti = 0
+
+var box = map[int]string{
+	0: "大吉",
+	1: "中吉",
+	2: "小吉",
+	3: "凶",
+	4: "大凶",
+}
+
+var syougatu = [...]string{
+	"01-01",
+	"01-02",
+	"01-03",
+}
+
+type nower interface {
+	Now() time.Time
+}
+
+type intner interface {
+	Intn(int) int
+}
+
+type response struct {
+	Result string `json:"result"`
+}
+
+type omikuji struct {
+	nower
+	intner
+	response
+}
+
+func (o *omikuji) open(w http.ResponseWriter, r *http.Request) {
+	o.pickUp()
+	buf := o.encodeJson()
+	fmt.Fprintf(w, buf.String())
+}
+
+func (o *omikuji) encodeJson() bytes.Buffer {
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(o.response); err != nil {
+		log.Fatal(err)
+	}
+	return buf
+}
+
+func (o *omikuji) pickUp() {
+	if isOsyougatu(o.Now()) {
+		o.Result = getDaikiti()
+	} else {
+		o.Result = box[o.Intn(5)]
+	}
+
+}
+
+func isOsyougatu(date time.Time) bool {
+	day := date.Format("01-02")
+	for _, sanganichi := range syougatu {
+		if day == sanganichi {
+			return true
+		}
+	}
+	return false
+}
+
+func getDaikiti() string {
+	return box[daikiti]
+}
diff --git a/kadai4/tokunaga/omikuji_test.go b/kadai4/tokunaga/omikuji_test.go
new file mode 100644
index 0000000..29fcd31
--- /dev/null
+++ b/kadai4/tokunaga/omikuji_test.go
@@ -0,0 +1,105 @@
+package main
+
+import (
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+type testNower struct {
+	now time.Time
+}
+
+type testIntner struct {
+	randInt int
+}
+
+func (t testNower) Now() time.Time {
+	return t.now
+}
+func (t testIntner) Intn(_ int) int {
+	return t.randInt - 1
+}
+
+func TestOpen(t *testing.T) {
+	shougatsu := testNower{now: time.Date(2018, 1, 1, 9, 11, 11, 11, time.UTC)}
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest("GET", "/omikuji", nil)
+	o := omikuji{nower: shougatsu, intner: testIntner{randInt: 5}}
+	o.open(w, r)
+	rw := w.Result()
+	defer rw.Body.Close()
+	if rw.StatusCode != http.StatusOK {
+		t.Fatal("unexpected status code")
+	}
+	b, err := ioutil.ReadAll(rw.Body)
+	if err != nil {
+		t.Fatal("unexpected error")
+	}
+	expected := `{"result":"大吉"}`
+	if s := strings.TrimSpace(string(b)); s != expected {
+		t.Fatalf("want: %s, got: %s", expected, s)
+	}
+}
+
+func TestEncodeJson(t *testing.T) {
+	expected := `{"result":"大吉"}`
+	o := omikuji{response: response{Result: "大吉"}}
+	actual := o.encodeJson()
+	if strings.TrimSpace(actual.String()) != expected {
+		t.Errorf("want: o.encodeJson() = %s, got: %s ", expected, actual)
+	}
+}
+
+func TestPickUp(t *testing.T) {
+	nenmatsu := testNower{now: time.Date(2017, 12, 31, 23, 59, 11, 11, time.UTC)}
+	shougatsu := testNower{now: time.Date(2018, 1, 1, 9, 11, 11, 11, time.UTC)}
+	cases := []struct {
+		name     string
+		input    omikuji
+		expected string
+	}{
+		{name: "お正月以外", input: omikuji{nower: nenmatsu, intner: testIntner{randInt: 5}}, expected: "大凶"},
+		{name: "お正月", input: omikuji{nower: shougatsu, intner: testIntner{randInt: 5}}, expected: "大吉"},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			c.input.pickUp()
+			if actual := c.input.Result; actual != c.expected {
+				t.Errorf("want o.Result = %v, got %v", c.expected, actual)
+			}
+		})
+	}
+}
+
+func TestIsOsyougatu(t *testing.T) {
+	cases := []struct {
+		name     string
+		input    time.Time
+		expected bool
+	}{
+		{name: "12/31", input: time.Date(2017, 12, 31, 23, 59, 11, 11, time.UTC), expected: false},
+		{name: "1/1", input: time.Date(2018, 1, 1, 9, 11, 11, 11, time.UTC), expected: true},
+		{name: "1/2", input: time.Date(2018, 1, 2, 10, 12, 11, 11, time.UTC), expected: true},
+		{name: "1/3", input: time.Date(2018, 1, 3, 11, 12, 11, 11, time.UTC), expected: true},
+		{name: "1/4", input: time.Date(2018, 1, 4, 0, 0, 0, 0, time.UTC), expected: false},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if actual := isOsyougatu(c.input); actual != c.expected {
+				t.Errorf("want isOsyougatu(%s) = %v, got %v", c.input, c.expected, actual)
+			}
+		})
+	}
+}
+
+func TestGetDaikiti(t *testing.T) {
+	expected := "大吉"
+	actual := getDaikiti()
+	if actual != expected {
+		t.Errorf("want: getDaikiti() = %s, got: %s ", expected, actual)
+	}
+}