The bare minimum is 55 moves (4 moves for each pawn, 1 move for each rook and queen, 4 moves for each knight, 2 moves for each bishop, 7 moves for the king = 4*8 + 1*3 + 4*2 + 2*2 + 7*1 = 55). However, there are a lot of clashes: the only way for queen and rooks to get 1 move is to go across the board directly, and not both sides can do that; for each pair of rooks/queens in the same column, one must give way. If one gives way, the best I can see is 3 moves (e.g. Ra1-b1-b8-a8, Qd1-g4-g5-d8, etc). One side has to perform this maneuver twice, adding the total to at least 59 moves. That's a lower bound; not sure if that's achievable.
Circumnavigation in Hypothetical Chess
Sort:
Thank you Chaotic for your response, as you described each piece will face a spatial conflict with its opposite, this issue can be circumvented with maneuvers in the limited free space of the board, however this carries its own set of problems. First of course is efficiency, minimizing the number of turns is the entire purpose of the though experiment. The second issue appears when moving the kings; since a king can’t be put into check the order in which each piece moves must revolve around avoiding intersections of the king’s path and at the same time providing an opening to allow the two to switch places. If this particular problem can be solved, in theory, the complete solution would boil down to a rather simple sorting of the remaining pieces.
Note: Please forgive the abnormal nature of this puzzle, as it stands I have no formal solution to it, yet I believe it may be possible through ingenuity, mathematics, and proficient chess skills.
Given the constraints of the standard chess game, with an additional provision allowing pawns to move diagonally forward one space without requiring a piece to be taken, what is the minimum number of turns required for each piece to move to the corresponding rival’s starting position, i.e. white queen to D8, black queen to D1, white king to E8, black king to E1, and so on, essentially flipping the board. Pieces that have pairs and pawns do not necessarily have to be in there respected order and at no point can a piece be taken, the king be put in checkmate, or a pawn be promoted.