How to Improve Mental Endurance

In my attempt to get better, I played my first 20/40 move/minutes game on the computer, writing down moves and staring at my board instead of the screen.  I didn't really understand that this meant the game could go on for around 2 hours, so when it did I was mentally exhausted.  All my OTB chess has been blitz/short standard (usually no more than a 30 minute game), so this was way out of my league.  I ended up wasting away an even endgame by giving my opponent an easy fork.  I guess I should add that I got a few vaccinations the day before, and am experiencing the side effects, so maybe that is the culprit.

But in general, how does one improve their mental stamina/endurance to maintain your best play throughout a long game?

I think there are two good ways to improve your mental stamina.

The first is to play long time control games regularly. I try to play a 90 minute with 5 second delay game each day on-line. This will keep my mind active and prepare me for tournaments when I will have to play 2 or 3 long games in 1 day.

The second is to regularly go through  chess puzzles. The resource I like to use for this is the "Chess Tactics Server", http://chess.emrald.net/ , each day I try to log onto this site and do 50 puzzles. This has really helped me to prepare myself for the intense mental focus needed to play the longer time control games.

I hope that these suggestions will help you to improve your mental capabilities. 

MattHelfst, that some serious business! I am impressed! Thanks for the link to the Tactics Chess Server. I just registered.

Sprite, In addition to practice as MattHelfs has suggested, I would suggest taking a couple of breaks. Walk around, stretch, look away from the board, ... I am not sure that once can focus totally the whole time. When you come back to the game after a small break, you might should be sharp enough to tackle the issues at hand.

Making sure you have had enough sleep before playing these long games also helps.

http://www.betterhealth.vic.gov.au/BHCV2/bhcarticles.nsf/pages/Sleep_deprivation?OpenDocument

it is very important that you get rid of extra energy by doing some type of out door activity like running byking etc before the Long OTB game, while playing the game you need to step away from the board atleast every 13 to 15 minutes if the position allows it taking breaks of about 1 to 2 minutes even longer if you are really ahead on time, you need to make sure that you concentrate in the position and only take a break after you have made a move, when you come back to the table make sure you ask your opponent what his last move was and also look at the clock sometimes the fact that they made the move while you were not at the table makes them forget about pressing the clock, if they made the move and didn't press the clock you can tell them right away or just evaluated the position cleverly on their time and then reminding them about pressing the clock once you are ready to make your move (use it don't abuse it), to let your opponent's time run when they forget to press  the clock is not exactely gentlemanly, remember everytime you step away from the board and comeback you need to check the position for tactical tricks, most players have the impression that setting up tactical tricks when their opponents are not looking works, and infact it does work, what happen is that sometimes when you leave the board after making your move, you have your next move in mind, and some times you comeback to the table and make that move automatically without realizing your opponent had set up a trap, that's why you need to ask for your opponent what his/her last move was, and you need to re-evalute the position....

just some pointers.. good luck

Copious amounts of weed and alcohol. No but seriously, Botvinnik used to train by playing with background noise like radios, so the silence of a big match felt like an added bonus. If you've got a board type chess computer, try playing that at the same time as a PC version. Or if you have FRITZ 8-10, it'll let you play more than one game at the same time, like a simul. Another good way is playing through games out of books, twice. The first time just play through it quick, the second time study it a bit more. I read somewhere that this helps the memory with familiarity functions. Try to avoid games with loads of analysis though, as this may make you lose interest. 

I think regular excercise should imrpove mental stamina. Thinking over the board consumes a lot of energy as do physical activities. The longer the game goes on, the more energy is sapped from your body leading to oversights and blunders.

Just read all the ratatouie posts.

I agree with this one, man they were tough to read.

Try getting a physical exercise like runing or playing football it helps.

I think improving physical health is the entire key. I don't think doing a lot of tactical exercises will do much to improve your stamina, but it will improve your tactical vision. I don't think spending two hours completing one game takes more stamina than spending two hours completing 20 games; I think it's quite the opposite. You absolutely need your chess preparation, but if you are consistently being worn down mentally trying to survive sharp positions and end up playing way beneath your potential because you are becoming exhausted, you need to focus on the health of your entire body.