diff --git a/core/modules/user/src/Entity/User.php b/core/modules/user/src/Entity/User.php
index ff3e962..f8e87a1 100644
--- a/core/modules/user/src/Entity/User.php
+++ b/core/modules/user/src/Entity/User.php
@@ -460,7 +460,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
 
     // The name should not vary per language. The username is the visual
     // identifier for a user and needs to be consistent in all languages.
-    $fields['name'] = BaseFieldDefinition::create('string')
+    $fields['name'] = BaseFieldDefinition::create('user_name')
       ->setLabel(t('Name'))
       ->setDescription(t('The name of this user.'))
       ->setRequired(TRUE)
diff --git a/core/modules/user/src/Plugin/Field/FieldType/UserNameItem.php b/core/modules/user/src/Plugin/Field/FieldType/UserNameItem.php
new file mode 100644
index 0000000..89d8c29
--- /dev/null
+++ b/core/modules/user/src/Plugin/Field/FieldType/UserNameItem.php
@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\user\Plugin\Field\FieldType\UserNameItem.
+ */
+
+namespace Drupal\user\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\Plugin\Field\FieldType\StringItem;
+
+/**
+ * Defines the 'user_name' entity field type.
+ *
+ * This consists some logic regarding the emptyness of the anonymous user name.
+ *
+ * @FieldType(
+ *   id = "user_name",
+ *   label = @Translation("User name"),
+ *   description = @Translation("A field containing a username."),
+ *   category = @Translation("User"),
+ *   default_widget = "string_textfield",
+ *   default_formatter = "string"
+ * )
+ */
+class UserNameItem extends StringItem {
+  /**
+   * @inheritDoc
+   */
+  public function isEmpty() {
+    if ($this->getEntity()->id() === 0) {
+      return FALSE;
+    }
+    return parent::isEmpty();
+  }
+
+}
diff --git a/core/modules/user/src/Plugin/Validation/Constraint/UserNameConstraintValidator.php b/core/modules/user/src/Plugin/Validation/Constraint/UserNameConstraintValidator.php
index 12d4fa3..84eee45 100644
--- a/core/modules/user/src/Plugin/Validation/Constraint/UserNameConstraintValidator.php
+++ b/core/modules/user/src/Plugin/Validation/Constraint/UserNameConstraintValidator.php
@@ -49,6 +49,11 @@ public function validate($items, Constraint $constraint) {
     ) {
       $this->context->addViolation($constraint->illegalMessage);
     }
+    /* @var \Drupal\user\UserInterface $entity */
+    $entity = $items->getEntity();
+    if (!$entity->isAnonymous() && Unicode::strtolower($name) === 'anonymous') {
+      $this->context->addViolation($constraint->anonymousMessage);
+    }
     if (Unicode::strlen($name) > USERNAME_MAX_LENGTH) {
       $this->context->addViolation($constraint->tooLongMessage, array('%name' => $name, '%max' => USERNAME_MAX_LENGTH));
     }
diff --git a/core/modules/user/src/Tests/UserValidationTest.php b/core/modules/user/src/Tests/UserValidationTest.php
index c099dc3..d77d80e 100644
--- a/core/modules/user/src/Tests/UserValidationTest.php
+++ b/core/modules/user/src/Tests/UserValidationTest.php
@@ -180,6 +180,13 @@ function testValidation() {
     $this->assertEqual(count($violations), 1);
     $this->assertEqual($violations[0]->getPropertyPath(), 'roles.1');
     $this->assertEqual($violations[0]->getMessage(), t('The referenced entity (%entity_type: %name) does not exist.', array('%entity_type' => 'user_role', '%name' => 'unknown_role')));
+
+    $user->save();
+    $user->set('name', 'anonymous');
+    $violations = $user->validate();
+    $this->assertEqual(count($violations), 1, 'Anonymous is a reserved username.');
+    $this->assertEqual($violations[0]->getPropertyPath(), 'name');
+    $this->assertEqual($violations[0]->getMessage(), 'Anonymous is a reserved username.');
   }
 
   /**
diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index df17388..dd55b49 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -70,7 +70,6 @@ function user_install() {
     ->create(array(
       'uid' => 0,
       'status' => 0,
-      'name' => 'Anonymous'
     ))
     ->save();