Similarly, in Elevator Chess, the four central squares, e4, d4, e5, and d5, contain elevators.
When it is played on more than one board, each side starts with one full set of pieces on each board, makes one move per turn on each board, any piece on an elevator square has the option of making an elevator move instead of a normal move, and victory is achieved by winning a preponderance of the games.
When the game is played by mail or by email with one player per side, each player is able to make one move per board on each exchange, as long as it is her turn to play on that board; however, it is permissible to defer movement on one or more boards, as long as at least one move is made somewhere.
When the game is played by team, face-to-face, normally there will be one player per board, and each board will proceed at its own speed.
Kings may not ride the elevators.
When an elevator move is made, it uses up that side's turn on the board it leaves, but on the board where it arrives it does not. For example, suppose that while it is your move a friendly Knight suddenly appears on d5, giving check to the enemy King; you can capture the King, thus winning the game! (Note that doing so moves it off the elevator square.)
Notice that if you're playing in a game of 1000 boards, you only need to be aware of the boards to your right and left.
This is more fun than being blocked on one side, so it is legal, and even encouraged.
When the elevator to a floor is closed, elevator moves ignore it. In a team setting, this means that somebody is required to sit at the empty board and transfer pieces immediately in the proper direction.
(This rule is intended to be simple, to minimize stalling, and to give the winning side some advantage on other boards without starting a tidal wave of victories.)
For this reason there must also be a rule that when two consecutive boards have finished no transfers can be made through them.
One exception is the Nattering Nabobs of Negativity. If one side used this army, it could profit by transferring all of its negative-valued pieces to a board where it was losing anyway, and resigning that game.
Each player could also have a different army. This would be a bit confusing, but it could be fun if played with the right attitude. Two applicable rules are (1) a Fibnif making an elevator move remains a Fibnif; it does not become a Knight or a WD, or whatever is native to the board it arrives on. (2) a Pawn promotes to whatever is native to the board where it promotes.
The most common choices will probably be to play with two or three boards, but playing with as many as ten boards is probably doable.
There is no logical limit to the total number of boards, but of course it would be extremely difficult to arrange the physical facilities for a game between two teams of a hundred players each; the noise level would likely cause hearing loss in the participants.
In practice, teams of 3 to 6 players per side should be lots of fun.
With multiple players per side, Elevator Chess is not a substitute for Double Bughouse Chess, nor is it a direct competitor; but it should appeal to nearly the same set of players. Elevator Chess is more flexible with respect to the number of players per side, and perhaps offers a few more interesting strategies than bughouse does.
If you are winning big, you want to try to unload a few excess pieces and Pawns to your neighbors, and also to position something on an elevator square so that you can take advantage of the Victory Transfer.
Empty elevator squares are a great danger because enemy pieces may appear there, but they are also a great benefit because friendly pieces may show up. Conversely, occupied elevator squares block arrivals.
In both cases, the rule of touch-move is waived. You must replace the piece you tried to move on its original square, but then you are free to make any other legal move.
"Displaced Elevator Chess" would be the name of a game where the elevator squares were in different locations on different boards.
It makes almost no difference to the game on your board if your neighbor to the right is playing Billiards Chess or Cylindrical Chess, or even if your neighbor is playing on a 10x10 board.
In Automatic Elevator Chess, each turn e4 and d4 move up while e5 and d5 move down, a conveyer-belt type of action. This would happen Avalanche-style, after each player's move, and it would require that all of one side's boards be played at the same time.
In 3D Elevator Chess, the central cube of 8 locations would be elevator squares, moving pieces in the fourth dimension from one 8x8x8 chessboard to the next.
In 7x7 Elevator Chess, only the centermost square is an elevator square.
In Elevator Chess for Many Teams, you might for example have 4 teams of 2 players each playing on 4 boards; Team A could play White on boards 1 and 2, while team C had Black on boards 2 and 3.
When played between two players with two boards, it is intrinsically a serious game, with great strategic interest; but when played between two multiplayer teams it is fundamentally a social game, lots of fun but don't take it too seriously.