It’s possible to play chess using email. This is possible because
there are notations like PGN (Portable Game Notation) that describe
the state of a game.
By playing on your computer and sending the PGN of the game to
your opponent, that person will be able to play their move and
send you the new PGN so you can play.
Using xboard
This is quite easy with xboard (which should be available in most
bsd/linux/unix distributions), as long as you are aware of the few
keybindings.
When you start a game, press Ctrl+E to enter edition mode, this
will prevent the AI to play, then make your move.
From there, you can press Ctrl+C to copy the state of the game.
You will have something like this in your clipboard.
[Event "Edited game"]
[Site "solene.local"]
[Date "2020.09.28"]
[Round "-"]
[White "-"]
[Black "-"]
[Result "*"]
1. d3
*
You can send this to your opponent, but the only needed data is 1.
d3 which is the PGN notation of the moves. You can throw the rest.
In a more advanced game, you will end up mailing this kind of data:
1. d3 e6 2. e4 f5 3. exf5 exf5 4. Qe2+ Be7 5. Qxe7+ Qxe7+
When you want to play your turn, load that line and press Ctrl+V,
you should see the moves happening on the board.
Using gnuchess
gnuchess allow playing chess in command line.
When you want to start a game, you will have a prompt, type manual
to not play against the AI. I recommend using coords to display
coordinates on the axis of the board.
When you type show board you will have this display:
white KQkq
8 r n b q k b n r
7 p p p p p p p p
6 . . . . . . . .
5 . . . . . . . .
4 . . . . . . . .
3 . . . . . . . .
2 P P P P P P P P
1 R N B Q K B N R
a b c d e f g h
Then, I can type d3 I get a display
8 r n b q k b n r
7 p p p p p p p p
6 . . . . . . . .
5 . . . . . . . .
4 . . . . . . . .
3 . . . P . . . .
2 P P P . P P P P
1 R N B Q K B N R
a b c d e f g h
From the game, you can save the game using pgnsave FILE
and load a game using pgnload FILE.
You can see the list of the moves using show game.