just curious as to who actually invented the first version of the coin matrix, since it seems to be just as ancient as cups and balls i'm not sure if it can actually be credited to a person in the first place. also if anyone knows anything about the later variations and all that, please do share with everyone else (e.g. only four by daniel garcia).

also what was the name of the matrix that jack liw did on youtube involving only the hands? and also does anyone know the difference between shade and four only?

boon han

It was Al Schneider who invented and popularised the matrix.

Yank Hoe's "Sympathetic Coins" (which was first described in T. Nelson Downs' "The Art of Magic" and also in J.B. Bobo's "Modern Coin Magic") also had an impact on the development of the matrix.

I believe that a coin matrix is strictly defined as a coin assembly using cards as covers. So not all coin assemblies can be considered matrix effects, for example, those using only the hands (which I think is cleaner, effect-wise, though it might be confusing if not performed well).