diff --git a/mercurial/templatekw.py b/mercurial/templatekw.py
--- a/mercurial/templatekw.py
+++ b/mercurial/templatekw.py
@@ -554,6 +554,14 @@ def shownamespaces(context, mapping):
 
     return _hybrid(f, namespaces, makemap, pycompat.identity)
 
+@templatekeyword('negrev', requires={'repo', 'ctx'})
+def shownegrev(context, mapping):
+    """Integer. The repository-local changeset negative revision number,
+    which counts in the opposite direction."""
+    ctx = context.resource(mapping, 'ctx')
+    repo = context.resource(mapping, 'repo')
+    return scmutil.intrev(ctx) - len(repo)
+
 @templatekeyword('node', requires={'ctx'})
 def shownode(context, mapping):
     """String. The changeset identification hash, as a 40 hexadecimal
diff --git a/tests/test-obsmarker-template.t b/tests/test-obsmarker-template.t
--- a/tests/test-obsmarker-template.t
+++ b/tests/test-obsmarker-template.t
@@ -2429,6 +2429,23 @@ Check other fatelog implementations
      date:        Thu Jan 01 00:00:00 1970 +0000
      summary:     ROOT
   
+Check that {negrev} shows usable negative revisions despite hidden commits
+
+  $ hg log -G -T "{negrev}\n"
+  @  -3
+  |
+  o  -4
+  
+
+  $ hg log -G -T "{negrev}\n" --hidden
+  x  -1
+  |
+  | x  -2
+  |/
+  | @  -3
+  |/
+  o  -4
+  
 
 Test templates with splitted and pruned commit
 ==============================================
@@ -2639,3 +2656,10 @@ metadata should be converted back to loc
   |/     Obsfate: rewritten using amend as 2:718c0d00cee1 by test (at 1970-01-01 00:00 +0000);
   o  ea207398892e
   
+  $ hg log -G -T "{negrev}\n"
+  @  -1
+  |
+  o  -2
+  |
+  o  -5
+