diff --git a/src/main/java/com/jsoniter/output/StreamImplString.java b/src/main/java/com/jsoniter/output/StreamImplString.java
index 7116f359..cbab7bca 100644
--- a/src/main/java/com/jsoniter/output/StreamImplString.java
+++ b/src/main/java/com/jsoniter/output/StreamImplString.java
@@ -48,7 +48,7 @@ class StreamImplString {
 
     static {
         for (int i = 0; i < CAN_DIRECT_WRITE.length; i++) {
-            if (i > 31 && i < 126 && i != '"' && i != '\\') {
+            if (i > 31 && i <= 126 && i != '"' && i != '\\') {
                 CAN_DIRECT_WRITE[i] = true;
             }
         }
diff --git a/src/test/java/com/jsoniter/output/TestString.java b/src/test/java/com/jsoniter/output/TestString.java
index 96dda062..91814dc9 100644
--- a/src/test/java/com/jsoniter/output/TestString.java
+++ b/src/test/java/com/jsoniter/output/TestString.java
@@ -8,6 +8,10 @@ public void test_unicode() {
         String output = JsonStream.serialize(new Config.Builder().escapeUnicode(false).build(), "中文");
         assertEquals("\"中文\"", output);
     }
+    public void test_unicode_tilde() {
+        String output = JsonStream.serialize(new Config.Builder().escapeUnicode(false).build(), "~");
+        assertEquals("\"~\"", output);
+    }
     public void test_escape_control_character() {
         String output = JsonStream.serialize(new String(new byte[]{0}));
         assertEquals("\"\\u0000\"", output);