What is the least amount of chess pieces you can use to cover the board with their possible moves and what is their placement? You can only use the pieces that are found on the chessboard (from the one side) at the start of the game (for example, you only have one queen, two knights, two rooks, etc.). Similar to this, but there is a piece requirement. Here is an example of the "coverage" of a knight and a queen (however, the pieces themselves would be covered as well):
Here is an upper bound. Since is has been proven that 8 pieces, with opposite colored bishops since the question asks for starting pieces only, that only 63 squares can be covered. Addding a single pawn works since occupied sqaures count as covered.
I say upper bound because all of the sqaures occupied by the pieces are also attacked, which is not needed under the confines of this question. Perhaps it could be down with one or two less pieces.