I plan on making a 72 cell game board with 42 different pieces. the cells on the board are conductive and connected to the arduino. the pieces have resistors inside of them to act as an identifier. when i place a piece on the conductive board, the resistor will be read by the arduino, thus, identifying the unique piece. My question is how do i eliminate the debounce when a player places a piece on a cell? I'm having a hard time thinking because 72 analog inputs means i'll be using multplexers. i don't plan to use any other way of identifying the pieces other than this because all the other sensors cannot support the mechanics of the game.
You could perhaps cheat and use the Bounce library? 
So you will have 42 different resister values to read? Or will some pieces have the same resistance, like pawns in chess?
What is the plan to ensure good contact with the 2 resister leads between piece & board?
Connecting five 16:1 4051's to 5 analog puts?
Letting the analog signal by taking a few readings over 10-15 mS would be sufficient.
Or have the players smack a button with a triumphant slap of the palm and a theatrically exclaimed "Take that!" so the arduino knows when a move is done.
Just curious about 72 - 8x9 grid? 6x12? 8 groups of 3x3?
it's 8x9. there are 21 different pieces and each player have 1 of each of the pieces. a button that signals the arduino that a move was made was a good idea but then i'm trying to sense when a move was made when a move was made.nothing more. ]
it's harder but it will would cooler for the board. thanks for all of your ideas btw 8)