The accurate way would actually be to stack 8 boards on top of each other with the rules you mentionned. This way the third dimension would be equivalent to the two firsts. But then you might want to add new pieces too to compensate for the extra free space created.

Btw, the concept of 3d chess by stacking boards was already imagined long ago, even before computers existed, by people who were already thinking about reforming chess or creating more variants. Some of these people centuries ago correctly predicted that we would one day create very weird and much more complex versions of this noble game. If only they saw this.

Very good post otherwise. I think it would be a great idea to update the 5D chess with the option to really allow the 3rd dimension, after exploring many different ways to do it (thanks to a simple box to tick or not when creating the game)

How about spherical boards, where the piece can move off the edge and to the other side?

Please.
You don't have to do this.

The 3rd physical dimension should have 8 boards stacked on the default board.

Tbh this game is already crazy so I think the Accurate Way would be what they'd implement. Though they'd probably add another piece that'd move in all five directions (like the Unicorn and Dragon but for all 5 dimensions) and make things even crazier.

They should add a mode where it doesn't add the third dimension though, that way if someone doesn't want to deal with that additional chaos they don't have to worry about it. But for those who like it, they can play it.

bruh

Misc
I didn't know where to put this so... it's here now.
-Each side of a cube is an independent board, just like how each board in a timeline is it's own board. If that needs explaining, the best way I can put it is, "A cube is nothing more than 6 squares glued together." Each cube is just 6 boards glued together so your brain can have a meltdown sooner.

Please ask question if needed or if you're curious! It's 2 AM and I completely understand if this is confusing or unclear. I can always try to draw examples, but I'm not good at drawing, so let's try words first.

Part 4/4

Time Travel, Alternate Timelines, Timeline Jumping
Each side of the cube is it's own board when it comes to this.
I'm going to use different pieces to explain specifics, but the general idea is applied to all pieces
-Cannot directly change sides by time travel; must use leftover movement (if any) to change sides
*Explanation: Rooks cannot jump to another side when time traveling, but bishops,
knights, etc. can. Sorry if that doesn't help*
-Alternate timelines do not affect other sides of the board; only the side you move to is changed in the new timeline
*If you go from one side to the other, the side you end your move on is what changes, not
the initial side. Staying on initial side changes only initial side*
-Cannot timeline jump to a different side of the cube directly; movement allowed after initial transition/jump is allowed to switch sides
*Similar to time travel rules from this section*

Part 3/4

Movement
Movement is a bit wonky, but I don't think it's harder than anything already in-game.
Lets take a queen in the middle of a side on a 3x3x3 cube/board/thing.
-Queen can move forwards, backwards, left, right, diagonal, and also go around the cube by doing so
-If the queen moves forward 4 spaces, then she gets put onto the bottom middle of the next side
*Would have to add true/official Up/Down, Left/Right, Forwards/Backwards indicators*
-To prevent going around the cube forever in one direction, the space occupied before moving isn't selectable and blocks movement (if that makes sense)
-Moving diagonally can either be limited to the side you're currently on
-Or allow limited side changes when going past a corner square to another side
*Limited to prevent just wrapping around the board as much as they want*
-Going diagonal past a non-corner square moves you over and up/over and down (diagonal up and down respectively)

Part 2/3

Sorry if this is implied or already said, but why not make the boards into sides of a cube?

Visuals
-Add an arrow or some simple graphic to allow rotation of the cube
*Could also use control and WASD to rotate and middle mouse button. Clicking blank
squares on a side will bring into focus, similar to clicking on a blank space now in
current game*
-Rotation of cube also rotates all other boards across timelines
*Could be optional and/or only rotate boards you can move to/boards in same
timeline/parallel boards/etc.*
-Moving a piece to another side of the cube simply rotates the cube on an axis/point while slowly moving the piece to it's end 2D position, similar to when moving back in time with the special transitions but rotation of a cube
*Might be able to get away with 2D animation with shading if an 3D object won't be easy*

Part 1/3 (Character limit)