Kriegspiel is a chess variant where neither side is allowed to see the locations of the opponent's pieces. This Kriegspiel round-robin tournament was contested over email between April 1, 1996 and December 4, 1997. It was conducted under the auspices of NOST according to these rules.
The third player would referee the game between the other two players -- he was the gateway through which all email about the game was sent. Our consensus was that this game is unsuited to postal play without special-purpose software, because it is too difficult and tedious for the referee to insure the correctness of his responses. During the games there were several referee errors and in fact game B had to be scratched when an email about the game was accidentally sent to the wrong player! It seems to me that Kriegspiel is much better experienced through over-the-board play or by having a computer referee as on the Internet Chess Club.
Here are all 6 games in PGN format. PGN doesn't tell the full story, however, since it is more informative to see what moves were attempted. Here are the games with all the attempted moves. Some have been annotated.
A Mallett-Voorhees 1-0 "Laying Bishop Traps" B Voorhees-Mallett * "Dances with Rooks" C Keller-Voorhees 0-1 unannotated D Voorhees-Keller 1-0 unannotated E Keller-Mallett 0-1 "Passed Pawns Must Be Pushed" F Mallett-Keller 1-0 "Finding the King"