Replacement Chess

Rules

Each piece that is taken from the opponent is placed back on an empty square by the player that made the capture, such that

1. Bishops are placed on a square of the same color the bishop was on when it was captured. This rule makes sure that the bishops of a player always stay on squares of different colors.
2. Pawns are not placed on the first or last row.

Of course, one may not place a piece where it checks ones king. One may resolve a check by taking a piece of the opponent and placing it between the checking piece (queen, rook, or bishop) and ones king.

Note that when white captures a black piece, white decides where the black piece is put back.

A variant: Putback chess

Again, pieces taken from the opponent must be placed back on the board, but there are now no restrictions on where bishops and pawns may be placed. When a player puts a captured pawn on its promotion row, then the player that owns the pawn decides to what piece it promotes. Pawns on the first row can make a double, and even a triple step forward, hence, a pawn on d1 can move to d2, d3, and d4, and take on c2 and e2. On all squares passed by such a double or triple step, the pawn can be taken en passant, so after d1-d4, the white pawn can be taken en passant on d2 or d3.