diff --git a/runtime/doc/index.txt b/runtime/doc/index.txt
index 6b7c822..d6957f5 100644
--- a/runtime/doc/index.txt
+++ b/runtime/doc/index.txt
@@ -781,6 +781,7 @@
 |gn|		gn	      1,2  find the next match with the last used
 				   search pattern and Visually select it
 |gm|		gm		1  go to character at middle of the screenline
+|gM|		gM		1  go to character at middle of the text line
 |go|		go		1  cursor to byte N in the buffer
 |gp|		["x]gp		2  put the text [from register x] after the
 				   cursor N times, leave the cursor after it