diff --git a/Modules/_json.c b/Modules/_json.c
index 89b0a41dd10acb..074115a355a1f4 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -360,13 +360,6 @@ _build_rval_index_tuple(PyObject *rval, Py_ssize_t idx) {
     return tpl;
 }
 
-static inline int
-_PyUnicodeWriter_IsEmpty(PyUnicodeWriter *writer_pub)
-{
-    _PyUnicodeWriter *writer = (_PyUnicodeWriter*)writer_pub;
-    return (writer->pos == 0);
-}
-
 static PyObject *
 scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next_end_ptr)
 {
@@ -385,10 +378,7 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
     const void *buf;
     int kind;
 
-    PyUnicodeWriter *writer = PyUnicodeWriter_Create(0);
-    if (writer == NULL) {
-        goto bail;
-    }
+    PyUnicodeWriter *writer = NULL;
 
     len = PyUnicode_GET_LENGTH(pystr);
     buf = PyUnicode_DATA(pystr);
@@ -419,12 +409,11 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
 
         if (c == '"') {
             // Fast path for simple case.
-            if (_PyUnicodeWriter_IsEmpty(writer)) {
+            if (writer == NULL) {
                 PyObject *ret = PyUnicode_Substring(pystr, end, next);
                 if (ret == NULL) {
                     goto bail;
                 }
-                PyUnicodeWriter_Discard(writer);
                 *next_end_ptr = next + 1;;
                 return ret;
             }
@@ -432,6 +421,11 @@ scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next
         else if (c != '\\') {
             raise_errmsg("Unterminated string starting at", pystr, begin);
             goto bail;
+        } else if (writer == NULL) {
+            writer = PyUnicodeWriter_Create(0);
+            if (writer == NULL) {
+                goto bail;
+            }
         }
 
         /* Pick up this chunk if it's not zero length */
@@ -1476,13 +1470,13 @@ encoder_listencode_obj(PyEncoderObject *s, PyUnicodeWriter *writer,
     int rv;
 
     if (obj == Py_None) {
-      return PyUnicodeWriter_WriteUTF8(writer, "null", 4);
+      return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter *)writer, "null", 4);
     }
     else if (obj == Py_True) {
-      return PyUnicodeWriter_WriteUTF8(writer, "true", 4);
+      return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter *)writer, "true", 4);
     }
     else if (obj == Py_False) {
-      return PyUnicodeWriter_WriteUTF8(writer, "false", 5);
+      return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter *)writer, "false", 5);
     }
     else if (PyUnicode_Check(obj)) {
         PyObject *encoded = encoder_encode_string(s, obj);
@@ -1649,7 +1643,7 @@ encoder_listencode_dict(PyEncoderObject *s, PyUnicodeWriter *writer,
 
     if (PyDict_GET_SIZE(dct) == 0) {
         /* Fast path */
-        return PyUnicodeWriter_WriteUTF8(writer, "{}", 2);
+        return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter *)writer, "{}", 2);
     }
 
     if (s->markers != Py_None) {
@@ -1753,7 +1747,7 @@ encoder_listencode_list(PyEncoderObject *s, PyUnicodeWriter *writer,
         return -1;
     if (PySequence_Fast_GET_SIZE(s_fast) == 0) {
         Py_DECREF(s_fast);
-        return PyUnicodeWriter_WriteUTF8(writer, "[]", 2);
+        return _PyUnicodeWriter_WriteASCIIString((_PyUnicodeWriter *)writer, "[]", 2);
     }
 
     if (s->markers != Py_None) {