diff --git a/src/doc/screen.1 b/src/doc/screen.1
index 80c6483..b781e3a 100644
--- a/src/doc/screen.1
+++ b/src/doc/screen.1
@@ -509,7 +509,7 @@ automatic margins on and off).
 .PD
 Send a control-s to the current window.
 .IP "\fBC-a S\fP	(split)"
-Split the current region into two new ones.
+Split the current region horizontally into two new ones.
 See also \fIonly, remove, focus\fP.
 .IP "\fBC-a t\fP"
 .PD 0
@@ -582,6 +582,8 @@ Shows where
 comes from, where it went to and why you can use it.
 .IP "\fBC-a _\fP	(silence)"
 Start/stop monitoring the current window for inactivity.
+.IP "\fBC-a |\fP	(split -v)"
+Split the current region vertically into two new ones.
 .IP "\fBC-a *\fP	(displays)"
 Show a listing of all currently attached displays.
 
@@ -2729,12 +2731,13 @@ The default is currently \*Q=s dd\*U (standout, default colors).
 .sp
 .ne 3
 .B split
+.RB [ -v ]
 .PP
 Split the current region into two new ones. All regions on the
 display are resized to make room for the new region. The blank
-window is displayed on the new region. Use the \*Qremove\*U or the
-\*Qonly\*U command to delete regions.
-Use \*Qfocus\*U to toggle between regions.
+window is displayed on the new region. Splits are made horizontally
+unless -v is used. Use the \*Qremove\*U or the \*Qonly\*U command
+to delete regions. Use \*Qfocus\*U to toggle between regions.
 .sp
 .ne 3
 .B "startup_message on\fP|\fBoff"
diff --git a/src/doc/screen.texinfo b/src/doc/screen.texinfo
index 1acabe2..cfcbafe 100644
--- a/src/doc/screen.texinfo
+++ b/src/doc/screen.texinfo
@@ -705,7 +705,7 @@ Send a ^S (ASCII XOFF) to the current window.  @xref{XON/XOFF}.
 
 @item @kbd{C-a S}
 (split)@*
-Split the current region into two new ones.  @xref{Regions}.
+Split the current region horizontally into two new ones.  @xref{Regions}.
 
 @item @kbd{C-a t}
 @itemx @kbd{C-a C-t}
@@ -799,6 +799,10 @@ Delete the screen-exchange file.  @xref{Screen Exchange}.
 (silence)@*
 Start/stop monitoring the current window for inactivity. @xref{Silence},
 
+@item @kbd{C-a |}
+(split -v)@*
+Split the current region vertically into two new ones.  @xref{Regions}.
+
 @item @kbd{C-a ,}
 (license)@*
 Show the copyright page.
@@ -1808,11 +1812,20 @@ which can contain different windows.
 @node Split, Focus,  , Regions
 @section Split
 @kindex S
-@deffn Command split
-(@kbd{C-a S})@*
+@kindex |
+@deffn Command split [-v]
+(@kbd{C-a S}, @kbd{C-a |})@*
 Split the current region into two new ones. All regions on the
 display are resized to make room for the new region. The blank
-window is displayed on the new region.
+window is displayed on the new region. The default is to create
+a horizontal split, putting the new regions on the top and
+bottom of each other. Using -v will create a vertical split,
+causing the new regions to appear side by side of each other.
+
+With this current implementation of @code{screen}, scrolling data
+will appear much slower in a vertically splited region than one
+that is not. This should be taken into consideration if you need
+to use system commands such as @code{cat} or @code{tail -f}.
 @end deffn
 
 @node Focus, Only, Split, Regions