Zcash is a chain fork. It has a shared history. The first 570,000 blocks of Zcash are the same as the first 570,000 blocks of Ycash. Everyone in control of Zcash private keys will be able to use them to access the same amount of Ycash. There is a Ycash built upon Zcash's solution to The Privacy Problem. Ycash aims to address The Distribution Problem by ensuring that 90% of the coins are distributed via the mining process.