I know a lot of players make their moves right off the computer screen like chess was a video game, but most players either set up the position on a board or use a program to keep track of the position using an analysis board or software to analyze. Using software is the problem. Actually, the use of software isn’t the problem, it’s just plain carelessness.
Usually you have a lot of analysis saved and it can be easy after selecting a move to jump to the server screen and make your move without really looking at the position. If you aren’t careful to double check that the position on the server board is the same as the one on your program’s screen, you can send the wrong move. Sometimes it just isn’t the optimal move, sometimes it will cost you the game.
Last year I had one game that went: 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.e5 Be7? And after I played 5.exf6 my opponent resigned. Obviously he had been expecting the more popular 4.Bg5 after which 4…Be7 is acceptable, didn’t look at the position when he played his 4th move and had to resign after I captured his N
Or, take the following position where I was Black. I should have played 6…b5 and then after 7.Bb3 there is a wide choice of moves. I was intending to play 7…Nf6 and with that move in mind, I played it immediately. It’s not that 7…Nf6 is all that bad, but the train wreck that followed was due to my careless mindset.
I was all mixed up. After 6…Nf6 the game continued 7.d4 and now I played 7…Bb6?? (7…exd4 is acceptable and, I suppose, so is 7…Ba7) 8.d5 0–1 More recently, I had this disaster:
I spend a lot of time trying to find a line that gave me a halfway decent position but couldn’t and so instead of wasting time on a lost game decided to resign and concentrate on my other games.
In his preparation for the 10th World Correspondence Championship the eventual winner, Victor Palciauskas, wrote, “It's bad enough to be beaten by your opponent's fine play, but it's much more painful when you beat yourself. Recording errors have plagued me during most of my CC career. Often I see the forest, but not the trees. I develop a deep plan and write down the next move incorrectly.”
This was the last WCCC played by mail and Palciauskas was determined not to let any recording errors ruin his chances. His advice to check and recheck, then check again is still good even on server play.