[ncwwmudt] Largest mating net

Chess construction task: What is that greatest number of one's chess pieces that can be involved in giving checkmate?

A piece can participate in checkmate in a great many ways.  It can give check, protect the piece giving check from capture by the king, cover a flight square, prevent interposition by blocking or by a pin, block another piece from capturing the piece giving check. In general, a piece participates if the piece weren't there, it wouldn't be checkmate.

In the variant allowing equal number of moves, a white piece can also prevent black from capturing the white king one move later.