When you're sitting at a chessboard, thinking about what to do two moves from now, you're thinking about a position that's not the same as the one on the board; and so, you see, you're playing blindfold chess, at least to some extent.
Of course, different degrees of ability, experience, and practice at playing "blindfold" exist. I suspect that few chessmasters need to use a chessboard when casually reading games from books and magazines, although they may prefer to use one when carefully studying games.
When you've played enough chess to become a master, you carry around a chessboard inside your head, and the mental chessboard is very convenient to use: it's lightweight, the pieces never get lost, the board never gets dirty, you never need to put it away after you're finished, and you can use it at times and in places where people would disapprove of your using a physical board and pieces.
This is not to say that every master has the blindfold ability of a Najdorf or a Koltanowski. However, the great blindfold players have freely discussed the tricks they used to help them achieve such extremes, and it's probably reasonable to guess that most masters could learn to play four simultaneous blindfold games against weak players, and most 1800 players could learn to read games without a board, and possibly even learn to play a whole game blindfolded (making weaker moves than normal, but perhaps not worse than a 1700 player would play when seeing the board).
When I started thinking about 8x8x8 3D Chess, I found myself in the unfamiliar situation of being unable to play blindfold. Since I don't have an 8x8x8 board, I was forced to try.
At first, it would take me 5 or 10 minutes just to figure out a legal move from some position in the early opening. After 3 months of thinking about 3D Chess for a few minutes of most days, I find that I can make many moves very quickly, but that I get bogged down and can't think after 15 or 20 moves.
Does that sound familiar? Many people who say they "can't play blindfold" have described their experiences to me using much the same words.
In 3D 8x8x8 Chess, I can't "see" the whole board at once blindfold. On the other hand, I'm not sure that I ever "see" the whole board at once in two-dimensional 8x8 Chess. What I "see" is not the board, but the relationships between the pieces: the Knight on f3 attacks the Pawn at e5, the Nc6 defends it, the Bb5 attacks the Nc6.
"The Japanese have 150 different words for Go moves." On their huge 19x19 board, they don't talk about squares like h4 or g5, but rather they talk about moves by describing their dynamic relationship with the nearest other pieces on the board in the current position: kosumi, hiraki, hane, tsukenobi, tsukehiki, warekomi, uchikomi; and there are enough different words that they can talk out a whole game this way.
Similarly, when I'm blindfold in a complex midgame of Chess, I don't picture the whole huge 8x8 chessboard with the pieces on it, and one ear broken off this Knight and a coffee stain on g3. Instead, I remember the interactions of the pieces with each other, and often I don't even remember all of those. Sometimes when the blindfold player stops to think, he might be reviewing the score of the game to try and remember if White's h-Pawn is still on h2, or if it moved to h3 ten moves ago.
After so many years of Chess, I know without thinking that f5 is a Knight's move away from g3, so if White moves a Knight away from g3 I check to see if he left something hanging on f5; then I make a mental note that there's a new attacker (Ne2) against d4, and go to work with the rest of the recent relationships between pieces.
I can easily decide to push my passed Pawn from d4 to d3 without ever needing to think about where my a-Pawn is, or whether the square b2 is empty, defended, or what.
In other words, I really only "see" part of the board, but I've had so much practice at switching around to see different parts that it feels as though I "see" the whole board.
In 3D Chess, however, I have a much harder time. On the 2D board, I know instantly and without thinking about it that a diagonal from d8 ends at h4; on the 3D board, I have to think about whether 5d8 leads to 1h4, and then whether 1h4 gives check to 4e1, and whether 1h4 attacks 4e4 (the gambit Pawn at 3f4 is in the way).
Even worse, there are so many pieces. I can learn the diagonals, and for now I can manage by the simple expedient of counting on my mental fingers: not the cumbersome "5d8, 4e7, 3f6, 2g5, 1h4", but the simpler "54321" because after all, I know d8-e7-f6-g5-h4, and in fact I have many memories both good and bad on each square.
But the pieces, so many pieces. My mental machinery is used to dealing with 16 pieces and a handful of pawns (I don't always remember where all the Pawns are). I really don't know if it's possible to remember that many pieces, where they are, what they're doing...
Now, I can visualize the 2x2x2 center of the board and a few squares around it, not a 4x4x4 cube, but basically the sphere inside the cube.
The problem is, when I visualize an area this big (or you could say "this small") inside some random area of the board, I have a lot of trouble figuring out what pieces are in it. The problem is that there are so many pieces.
One big help is the game score, the record of the moves played so far. When it is written out like this:
1. 4e2-4e4 4e7-4e5 2. 4f2-4f4 4e5:4f4 3. 4d2-4d4 4g7-4g5 4. 5d2-5d4 5d7-5d5 5. 4d4:5d5 Q5d8:5d5 6. B3f1-5d3 5f7-5f5 7. N5b1-5c3 B3f8-7b4 8. B4f1-4c4 Q5d5-5e6 9. N6g1-5g3! 5g7-5g6I can run my eye down one side of it and quickly see that the Bishop at 5f1 is still at home, that 5d3 is occupied by a B, and so on.
When I play blindfold chess on a two-dimensional 8x8 board, I have no trouble remembering all the moves of the game, and can mentally review the moves with ease. In 3D, however, I have trouble remembering the moves! It seems as though the same mental programs are used for remembering the moves, remembering the position, remembering the current locations of the pieces, and remembering the current relationships of pieces to each other; and so when part of it has trouble, so does the rest of it.
If you learn to play one game blindfold, or to read a game from a book, or to think about a position blindfold, it will help you become a better chessplayer.
If you learn to play four games at once against weaker players, it will not make you a better chessplayer, but it might lead to fun and free fino.
When I played a two game blindfold simul in the bar in Cadaque`s, against the mayor and a fellow from Texas, they tried to cheat: they tried to impair my play by plying me with plentiful potables.
The ploy was enjoyed but foiled.