diff --git a/src/calibre/db/search.py b/src/calibre/db/search.py
index 8d018c618b..332016a792 100644
--- a/src/calibre/db/search.py
+++ b/src/calibre/db/search.py
@@ -303,9 +303,9 @@ class BooleanSearch(object):  # {{{
         self.local_empty     = icu_lower(_('empty'))
         self.local_blank     = icu_lower(_('blank'))
         self.local_bool_values = {
-            self.local_no, self.local_unchecked, '_no', 'false', 'no',
-            self.local_yes, self.local_checked, '_yes', 'true', 'yes',
-            self.local_empty, self.local_blank, '_empty', 'empty'}
+            self.local_no, self.local_unchecked, '_no', 'false', 'no', 'unchecked', '_unchecked',
+            self.local_yes, self.local_checked, 'checked', '_checked', '_yes', 'true', 'yes',
+            self.local_empty, self.local_blank, 'blank', '_blank', '_empty', 'empty'}
 
     def __call__(self, query, field_iter, bools_are_tristate):
         matches = set()
@@ -315,20 +315,20 @@ class BooleanSearch(object):  # {{{
             val = force_to_bool(val)
             if not bools_are_tristate:
                 if val is None or not val:  # item is None or set to false
-                    if query in {self.local_no, self.local_unchecked, 'no', '_no', 'false'}:
+                    if query in {self.local_no, self.local_unchecked, 'unchecked', '_unchecked', 'no', '_no', 'false'}:
                         matches |= book_ids
                 else:  # item is explicitly set to true
-                    if query in {self.local_yes, self.local_checked, 'yes', '_yes', 'true'}:
+                    if query in {self.local_yes, self.local_checked, 'checked', '_checked', 'yes', '_yes', 'true'}:
                         matches |= book_ids
             else:
                 if val is None:
-                    if query in {self.local_empty, self.local_blank, 'empty', '_empty', 'false'}:
+                    if query in {self.local_empty, self.local_blank, 'blank', '_blank', 'empty', '_empty', 'false'}:
                         matches |= book_ids
                 elif not val:  # is not None and false
-                    if query in {self.local_no, self.local_unchecked, 'no', '_no', 'true'}:
+                    if query in {self.local_no, self.local_unchecked, 'unchecked', '_unchecked', 'no', '_no', 'true'}:
                         matches |= book_ids
                 else:  # item is not None and true
-                    if query in {self.local_yes, self.local_checked, 'yes', '_yes', 'true'}:
+                    if query in {self.local_yes, self.local_checked, 'checked', '_checked', 'yes', '_yes', 'true'}:
                         matches |= book_ids
         return matches