This is my way to visualize the board. I start by learning a quad, which is a 4x4 square. Lets take the bottom left Quad.
The quad has 16 squares. It is a good thing to memorize them when playing blindfold chess to help you play better. To remember the squares, there are several different ways. One way is to use diagonals. Since i know that a1 is a dark colored square, then i can say that the diagonal a1d4 is all black squares. Now that i konw this, then i can also know that the d1 square is W, so i can say the d1a4 diagonal is White squares. Another way to remember the squares is to use files. As we know that a1 is a dark square, then we also know that c1 is a dark square because you skip one square to get the same color. So the files a1a4 and c1c4 are B,W,B,W. The b1b4 and d1d4 files are W,B,W,B. Now we konw one quad and can even use this method to plug into the other three quad's (since all the four quads are identical) to understand the chess board better.Calculation/Blindfold play
How come everyone branched off the main purpose of this forum!! Its really quite annoying. Read the syllabus! i really agree with 2strong4u's comment though. Using the quadrant method helps with memorizing the board. Now what does calculation have to do with blindfold play? Calculation depends on the ability to visualize... and guess what? Blindfold play also entirely relies on this power  visualization  your mental eye!!! So then what is the difference between the two? Calculation you have a given point to begin at  a position in the chess board, and you must move the pieces in your head. Now Blindfold play u must start from the beginning!! So how often do we use these skills? Everyone calculates, the amateur player maybe 2 or 3 moves, the GM maybe 20! But not everyone plays blindfold play. So here's the secret  PLaying Blindfold your ability to calculate!! Why? Both are basedon Visualization!
Now as for as medical concerns for playing multiple boards at once? That's extremely hard to beleive. As long as one uses the other parts of the brain, (like physical activity, reading, math) what's the problem. The fact is that the average human only uses 25% of the brain's maximum in his/her lifetime.
Does blindfold mean looking at an empty board? I find even that difficult beyond about 10 moves.

blindfold means playing someone with out the chessboard.... just calling out the moves; playing the game in your head. Sometimes one person will have the board and pieces, while other turns his back to the game, as a handicap. The person who gets to look at the board obviously has the advantage. Both Players call out their moves. The person with the pieces makes moves for the blindfold player.
Using an empty board as an aid during blindfold play is not unheard of. In the Melody Ambers the players had such boards on their screens.
I think of that as lessthanblindfold though.
It's said that Najdorf, after WWII, played a 45 board blindfold simultaneous match, to appear in papers and show to his jewish relatives that he was still alive. Mind have powerfull unknown resources.
U should try it sometime. Playing blindfold really helps you understand the chess board... when you look at the board after the game and play it back the whole board seems much smaller. It may take awhile to play the game out, but it really is worth it.
The way I keep track of all the pieces is by remembering structures. Imagine white castled kingside, with his pawn on g3 and bishop on g2. You don't have to repeat all 6 pieces to yourself to remember that because you've seen it so much. That cuts down tremendously on how much you have to just remember.
I lose probably 400+ points playing blindfolded right now. Need to work on that.
Calculation is definitely harder, just in the fact that you have to keep the current position while calculating lines as well, and when you're done calculating a line, be able to revert to the current position without mixing anything up. It is good practice, and not as hard as it looks. Everyone should give it a try once they're familiar with the coordinates, maybe with a blank board to look at to start. It's nice to be able to just play a game of chess anywhere, anytime (if you have an opponent), with no board needed. (think on an airplane, waiting for a movie to start in the theater, waiting for your dinner to arrive, at a party, car ride...)
Kasparov certainly wasn't giving up 500 points blindfolded, and I'm certain he NEVER said that. Perhaps 100 points, probably less, depending on the time limit blindfolded. The faster, the weaker in relation to sighted.
I'm pretty certain he said itI just have to find the quote.
Just 100 points weaker when playing blindfold? I don't think that would pass any GM's smell test.
Maybe one will pop in and give her opinion.
It is entirely possible that the best players  Carlsen, Anand, Kasparov, Kramnik, Ivanchuk, Aronian, and perhaps a few others  play every bit as well blindfolded as OTB. They keep hundreds or thousands of games within accessible memory, you think they need to look at the board? Watch Ivanchuk, half the time he just stares at the ceiling when it is his move! Is he watching spiders?
Again, I don't believe that Kasparov ever said he played blindfold at 500 points weaker than OTB, it is ridiculous on its face given his strength.
When I played in old "snail mail" postal events, six times reaching the Finals of the Golden Knights (US Open correspondence ch), I only rarely set up a board. Virtually all of my analysis was done blindfolded, while driving here to there at work, or walking in the woods or working in the yard, and it was also rare that I checked a move over a board before sending a reply.
It's a skill, independent of chess ability. I've known at least one USCF 1600 player who could consistently contribute to blindfold analysis discussions, and several 1800+ players.
How about some opinions of the GMs themselves?
Otherwise I don't see the debate being meaningfully advanced.
Of course, the ability to play blindfold will vary from player to player, even among GMs.
Some Melody Amber blind ratings:
1. Morozevich 2811
2. Kramnik 2809
3. Anand 2761
45. Aronian 2744
45. Svidler 2744
67. Leko 2735
67. Topalov 2735
8. Shirov 2734
9. Ivanchuk 2707
10. Kamsky 2705
11. Gelfand 2686
12. Karpov 2681
13. Bareev 2667
14. Lautier 2662
15. Almasi 2656
First, about the relation between calculation and blindfold: I'm sure there is one, but I would also bet money that if you took two, let's say, Class A players, one who calculates and uses tactics an inordinate amount, and one who relies on positions and understanding of ideas more than normally, I think a blindfold match between these two would be matched evenly, as long as it's not a crazy position, just because the positional player will already know the position he's going into quite well.
Also, even if you don't think that playing blindfold would help your play (I think it would) it's still interesting to play a game or two. I remember when I played my dad (he took a draw, but he probably could have won) I found it challenging, but also fun.
Looking at the board doesnt help you calculate. It's great as a reference point to begin, where as in blindfold is u forget the position your doomed. But one you start moving pieces with your mental eye, the board no longer helps. You have left it. Why look at it anymore? Fine.... you say most of the board is the same, only this part has changed.... and maybe this is so when you see a 3 move combo. The key is to focus on one part of the chess board! A quadrant... 16 squares. now maymbe not bottom left , or top right, maybe the center! Of course you must be aware of the other pieces of the board  the long rangers affect it, but thats beside the point. You must try calculating without looking at the board, but maybe closing your eyes, or staring at the ceiling, but whatever does it for you!
You're right it is a method, a real simple one too. You divide the board into 4 parts. with 2 imaginary lines , one vertical and one horizontal. Each part has 16 squares, a quadrant. Next step is to memorize one of them, since every quadrant is identical... as in coloring. When I say memorize I mean memorize what square is what color. So if you memorize the bottom left quadrant, you could start on a1  its black. Then you see b2, c3 and d4, so you see the diagonal. Then you look at the d1 a4 diagonal, its all white. SO you have 8 of the squares down. The rest we can just see in our head by color coding... if a1 is black then a2 must be white. and so forth. Sounds simple. It is. If you been playing for awhile then you will have a good feeling for what color a square if someone just gave you a random square. Once you got the quadrant you can use in a blindfold game you can focus one one part, but and you'll have a stronger global view, the whole board..... maybe you're attacking the king, or defending.
Another method/tip for playing blindfold is playing every move back in your head that has occured before saying your move aloud. If opponent says e4, dont just say e5. Think in your head e4, then e5, then out loud say e5. If he plays Nf3, then think e4, e5, Nf3, Nc6, then out loud tell your opponent Nc6. Yeah it takes awhile. But the every time you say the position becomes more clear in your head.
That is right. Blindfold chess does help increase your calculation skills. This is because when you play blindfold chess, it is just like playing a chess game with a board except you have to make moves in your mind and record them when you play blindfold chess where as in a chess game, you can close your eyes or look at the ceiling like 2awesome2beat has said in post 41, and just calculate some number of moves and open your eyes and look at the board. Calculating and blinfold chess can be said as the same because when you calculate, you dont look at the board, and you use the image of the board that is in your head to think about the possible variations and moves, and then you play those moves.
so far we have the quad., repetition of moves to enforce imagry., chunking., or structures., to assist memory., and lets add: number/color code., as odd or even numbers... ex a1 is black ., on the a line >all odd numbers are black., therefore even must be white., on the b line b1 is white therefore all white squares on bline are white., black squares must be odd etc...
Wow. That is an intresting concept isthatso. I have never actually thought about this. Knowing this method wll help me calculate better since when you calculate, you usually dont look at a chess board. My visualization of a chesss board is much more improved then what it used to be before. I think blind chess would be much easier since i would know what squares are not being attacked by other pieces of my opponents. With this method, you could determine any square on a chess board. This method can be used on files and ranks. Once you know one square from the file or rank, then you can find out the others by knowing that the colors alternate.
To calculate in blindfold chess, use algebra..
1. e4 (
using the coordinate graphing system is
(5,2) to (5,4).. using slope you can represent what pieces are which.. or if piece are in contact with your pieces or something even deeper.. (4  2 ) / (5  5) giving this a slope of 2 ... If black follows with E5 his slope would be 2. Since pawns capture diagnally their capture slope would be +1/1 or 1/+1 which is equals 0...
1. Nf3
(7,1) to (6,3) (31)/(67) = 2/1 == 2
while a knight "facing" the other way would have a slope of 2 etc..
you would have to play like that i suppose. :)
EDIT:
A B C D E F G represent 1 2 3 4 5 6 7 8 on the x axis
1. E4 (5,4) E5 (5,5)
what would happen if you played a game(OTB) with a board with no squares? and then did the same with squares. would the experience be the same? is there a problem .,if so it should also exist in blindfold., if squares., or spacial relationships are not recognized., how can u make sence of where things are?
Okay, I just lost to an AI rated 200 in Chessmaster (again) in blindfold. lol.
Can someone please give me some tips on it? I keep forgetting where the pieces are. If I knew where the pieces were exactly, and can see the blank board as I do in chessmaster, I feel I would have very little trouble.
I tried repeating the positions of the "out of place" pieces over and over in my head, repeatedly saying the AI pawns were on a5, c6, f6, e6, its queen was on c7 and knight on h5.
You need to know the board intimately.
Color of the squares, which squares share the same diagonal, how many moves it takes a knight to go from one square to another (and what squares it attacks along the way) etc.
Here's a useful tool to improve your blindfold play: http://chesseye.alexanderfleischer.de/