Note that you cannot map the Shift or Alt or Ctrl keys alone as they are key modifiers. You can also prefix the desired key sequence with a backslash (\) or comma (,) or underscore (_), etc. Most of the key combinations should work in GUI Vim. But some of the key combinations may not work in all the terminal emulators. The function keys in combination with Control, Alt and Shift can also be used. Try to use an unused key sequence in your maps. For example, to list all the locations where maps beginning with "," are defined, use the following command: In the above command, replace with the desired key sequence. To determine the script or plugin that defines a map for a key sequence, use the following command. To display the list of keys that are currently mapped, use the following commands: Some of the key sequences may be used by the existing Vim scripts and plugins. If you don't use some Vim functionality invoked by a particular key sequence or you have an alternate key sequence to use that functionality then you can use that key sequence in your maps. To get a list of the key sequences used by Vim, read the following help topic: If you use a key sequence in your map that is already used by Vim, then you will not be able to use the functionality provided by Vim for that key sequence. Many of the key sequences that you can enter from the keyboard are used by Vim to implement the various internal commands. In your private maps you should use key sequences that are not used by Vim and by other Vim plugins. Finding unused keys Further information: Unused keys