Famicom carts were a free-for-all, as there was no lockout chip in the console. NES carts, and SNES/Super Famicom carts, required a CIC chip to function (or els

Famicom carts were a free-for-all, as there was no lockout chip in the console. NES carts, and SNES/Super Famicom carts, required a CIC chip to function (or else the lockout chip in the console would prevent it from booting); this allowed Nintendo to control cartridge production. (Yes, a handful of third parties either illegally copied or figured out a way around the lockout chip for NES; but the vast majority of carts were manufactured by Nintendo themselves.)