time travel chess adjustments – addendum

In rereading my previous post about an alternative ruleset to time travel chess, I realized that there’s a flaw in the following rule adjustment regarding a piece that returns to the board after jumping forward in time:

If a piece opts to jump, they have to move in a way that’s legal for the board state at the time and then place a marker on that tile.  That square is then “protected” at that move, meaning that no piece can occupy that square at the time when the piece would drop, and that square cannot be in a state where in the turn after the piece drops the opposing player can immediately capture it.  Therefore any piece on that square would be forced to move off of it as a consequence of a time traveling piece about to materialize on it.

The primary problem is that all pieces aside from pawns have the ability to move back to a spot that they previously occupied – so if the “Arrival Point” has a piece on it and a time-jumped piece is going to land on it, then a piece that moves off of it would have the ability to capture the time-jumped piece immediately after it lands.  Also, there’s a potential problem of: what if multiple pieces have the ability to attack the Arrival Point when a time-jumped piece lands?

Therefore I think there has to be three addendums/revisions to that rule:

  1. An opponent’s piece is allowed to occupy an Arrival Point at the point of the time-jump drop – that results in that piece being captured.
  2. A piece that lands on an Arrival Point gets a one-move grace period where they can’t be captured.
  3. A player may not place pieces in their own Arrival Points in a manner that would occupy Arrival Points at the moment of a time jump.

The last rule is essentially “you can’t have a piece at an Arrival Point when you’re about to time jump there”, but it reaches beyond a single instance because what if a player has pieces in more than one Arrival Point and those Arrival Points happen in consecutive moves?  That needs to be accounted for when considering what moves are legal for all moves leading up to the last Arrival Point.

Regarding the idea that “a time-jumped move means that the opponent isn’t allowed to put you in check”, a part of me feels like that could be an effective defensive strategy, but another part of me feels like that’s an exploitable gimmick – a person could opt to try to place a time jump in every future move and effectively make it so that the opponent could never put them in check.  Then again, multiple time-jumps in a row makes a player incredibly vulnerable.  Say that a queen drops in move 5 and the next four moves are time-jump drops.  That gives your opponent four free moves to capture the queen and then escape capture while pieces are being time-jumped on the board.

Regardless of that vulnerability, an easy fix to address that problem is to create some sort of limitation on time travel – the straightforward approach would be something like “you can only have five pieces per multiverse that’s time-jumping at any given point”, but maybe a better approach would be “you can only have x pieces per multiverse that’s time-jumping at any given point where x is some fraction of the number of pieces you have remaining on the board.”  Off the top of my head, I’d say time-jump power would be limited to 4 for 12-16 pieces on the board, 3 for 9-11 pieces on the board, 2 for 6-8 pieces on the board, and 1 for 7 and below.


A discussion with my brother has presented an elegant solution to some of the lingering problems of this revision: consider a time jump piece’s arrival as not being its own move.  Instead it’s considered a “delayed end to the previous move” so that the Arrival Point creates a “start state” for the player to make its true move – which could be that arrival piece or not.

That fixes the fussy “one-move grace period” mechanic that is outside of the bounds of normal chess mechanics and also addresses the issue of the restricting the opponent from being able to place the player in check because now they can.

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