diff --git a/client/src/components/LoginBox.vue b/client/src/components/LoginBox.vue
index 69a13be..53c2dc2 100644
--- a/client/src/components/LoginBox.vue
+++ b/client/src/components/LoginBox.vue
@@ -10,26 +10,32 @@
 </template>
 
 <script setup lang="ts">
-import { useFetch, useRouter } from '#app'
-import { watch, ref, Ref } from 'vue'
+import { useRouter } from '#app'
+import { ref, Ref } from 'vue'
+import useAuth from '@/composables/useAuth';
+// import { useMyselfStore } from '~~/src/stores/MyselfStore'
+
+const { validate, setAuthCode } = useAuth()
+const router = useRouter()
+
+const vFocus = { mounted: (el: HTMLElement) => el.focus() }
 
 const authCode: Ref<string> = ref('')
 const errorMessage: Ref<string> = ref('')
 
-const vFocus = { mounted: (el: HTMLElement) => el.focus() }
+
+validate()
+  .then(() => router.push('/play'))
+  .catch(() => null)
 
 const login = (): void => {
   errorMessage.value = ''
+  setAuthCode(authCode.value)
 
-  const { data, pending } = useFetch(`/api/login?code=${authCode.value}`)
-
-  watch(pending, (newVal) => {
-    if (!newVal && data.value === 'ok') {
-      const router = useRouter()
-      router.push('/play')
-    } else if (!newVal) {
-      errorMessage.value = 'login failed'
-    }
+  validate().then(() => {
+    router.push('/play')
+  }).catch(() => {
+    errorMessage.value = 'login failed'
   })
 }
 </script>
diff --git a/client/src/composables/useAuth.ts b/client/src/composables/useAuth.ts
new file mode 100644
index 0000000..447078b
--- /dev/null
+++ b/client/src/composables/useAuth.ts
@@ -0,0 +1,26 @@
+import { useMyselfStore } from '~~/src/stores/MyselfStore'
+
+export interface useAuth {
+  validate(): Promise<void>
+  setAuthCode(authCode: string): void
+}
+
+
+export default () => {
+  const MyselfStore = useMyselfStore()
+
+  return {
+    validate: async (): Promise<void> => {
+      if (MyselfStore.authCode.length != 6) {
+        throw Error('login failed')
+      }
+      const resp = await $fetch(`/api/login?code=${MyselfStore.authCode}`)
+      if (resp !== 'ok') {
+        throw Error('login failed')
+      }
+    },
+    setAuthCode: (authCode: string): void => {
+      MyselfStore.setAuthCode(authCode)
+    }
+  }
+}
diff --git a/client/src/stores/MyselfStore.ts b/client/src/stores/MyselfStore.ts
new file mode 100644
index 0000000..193f43d
--- /dev/null
+++ b/client/src/stores/MyselfStore.ts
@@ -0,0 +1,14 @@
+import { defineStore } from 'pinia'
+
+export const useMyselfStore = defineStore('MyselfStore', {
+  state: () => {
+    return {
+      authCode: '',
+    }
+  },
+  actions: {
+    setAuthCode(authCode: string): void {
+      this.authCode = authCode
+    }
+  },
+})