Define an "elegant" checkmate as one in which
- the king is not on the edge of the board
- the king and each of the 8 squares surrounding it are each attacked by exactly one, different opponent piece. (In other words: 9 pieces each attack exactly one of those squares)
- none of the squares touching the king are occupied by pieces of the king's colour
For instance, this is an elegant checkmate:
8/3B1N2/2K5/8/4k3/1N1P2P1/2P2PP1/8 w - - 0 1
Now, what is the shortest game that leads to an elegant checkmate?