diff --git a/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonReader.kt b/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonReader.kt
index 749cd74f3..e9b9ee742 100644
--- a/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonReader.kt
+++ b/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonReader.kt
@@ -144,14 +144,20 @@ internal class JsonReader(private val source: String) {
                 ++current
                 continue
             }
-            val tc = charToTokenClass(c)
             currentPosition = current
-            return tc == TC_STRING || tc == TC_OTHER || tc == TC_BEGIN_LIST || tc == TC_BEGIN_OBJ
+            return isValidValueStart(c)
         }
         currentPosition = current
         return false
     }
 
+    private fun isValidValueStart(c: Char): Boolean {
+        return when (c) {
+            '}', ']', ':', ',' -> false
+            else -> true
+        }
+    }
+
     /*
      * Peeked string for coerced enums.
      * If the value was picked, 'consumeString' will take it without scanning the source.