diff --git a/sh/tmux.sh b/sh/tmux.sh
index 5d14b75..1f21ae4 100644
--- a/sh/tmux.sh
+++ b/sh/tmux.sh
@@ -6,6 +6,8 @@ rwx_tmux_setup() {
 	local file
 	file="${HOME}/.tmux.conf"
 	rwx_file_write "${file}" "\
+# first index number
+set-option -g base-index 1
 # display duration
 set-option -g display-time 1536
 # reload configuration