diff --git a/doc/usage/cmd/blkcache.rst b/doc/usage/cmd/blkcache.rst
index d3b2254..0329261 100644
--- a/doc/usage/cmd/blkcache.rst
+++ b/doc/usage/cmd/blkcache.rst
@@ -1,6 +1,9 @@
 .. SPDX-License-Identifier: GPL-2.0+
 .. Copyright 2023, Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
 
+.. index::
+   single: blkcache (command)
+
 blkcache command
 ================