diff --git a/src/languages/japanese.rs b/src/languages/japanese.rs
index 3f68e46..3f49869 100644
--- a/src/languages/japanese.rs
+++ b/src/languages/japanese.rs
@@ -30,4 +30,43 @@ impl Language for Japanese {
             Years => "年",
         }
     }
+    // Japanese doesn't separate words with spaces, so drop the default " "
+    // between the value, the unit, and the trailing "前": "5 分 前" -> "5分前".
+    fn between_value_and_word(&self) -> &str {
+        ""
+    }
+    fn between_chunks(&self) -> &str {
+        ""
+    }
+    fn override_space_near_ago(&self) -> &str {
+        ""
+    }
+}
+
+#[test]
+fn test() {
+    use super::super::Formatter;
+    use std::time::Duration;
+
+    fn test_with_formatter<L: Language>(mut f: Formatter<L>) {
+        f.min_unit(TimeUnit::Seconds);
+        assert_eq!(f.convert(Duration::from_secs(0)), "今");
+        assert_eq!(f.convert(Duration::from_nanos(42)), "今");
+        assert_eq!(f.convert(Duration::from_micros(42)), "今");
+        assert_eq!(f.convert(Duration::from_millis(42)), "今");
+        assert_eq!(f.convert(Duration::from_secs(42)), "42秒前");
+        assert_eq!(f.convert(Duration::from_mins(42)), "42分前");
+        assert_eq!(f.convert(Duration::from_hours(2)), "2時間前");
+        assert_eq!(f.convert(Duration::from_hours(24)), "1日前");
+        assert_eq!(f.convert(Duration::from_hours(7 * 24)), "1週間前");
+
+        f.num_items(2);
+        assert_eq!(f.convert(Duration::from_secs(3600 + 42)), "1時間42秒前");
+
+        f.min_unit(TimeUnit::Nanoseconds);
+        assert_eq!(f.convert(Duration::from_nanos(42)), "42ナノ秒前");
+    }
+
+    test_with_formatter(Formatter::with_language(Japanese));
+    test_with_formatter(Formatter::with_language(Japanese.clone_boxed()));
 }