diff --git a/_i18n/ja.json b/_i18n/ja.json
index b1afd02d..226d9ba0 100644
--- a/_i18n/ja.json
+++ b/_i18n/ja.json
@@ -8,13 +8,13 @@
     "SUMMARY_INTRODUCTION": "はじめに",
     "SUMMARY_TOGGLE": "目次",
     "SEARCH_TOGGLE": "検索",
-    "SEARCH_PLACEHOLDER": "検索すると入力",
+    "SEARCH_PLACEHOLDER": "入力して検索",
     "FONTSETTINGS_TOGGLE": "フォント設定",
     "SHARE_TOGGLE": "シェア",
     "SHARE_ON": "{{platform}}でシェア",
     "FONTSETTINGS_WHITE": "白",
     "FONTSETTINGS_SEPIA": "セピア",
-    "FONTSETTINGS_NIGHT": "夜",
+    "FONTSETTINGS_NIGHT": "ナイト",
     "FONTSETTINGS_SANS": "ゴシック体",
     "FONTSETTINGS_SERIF": "明朝体"
 }