Bitcoin Cash is a cryptocurrency and a hard forked version of the original Bitcoin. It shares many of the same protocols as bitcoin, such as Proof of Work SHA-256 hashing, 21,000,000 supply, same block times and reward system, but maintains two differences, namely 8MB block versus Bitcoin’s 1MB blocks and an increased rate of difficulty adjustment of every 6 blocks as opposed to Bitcoin’s every 2016 blocks.
BCH emerged in mid-2017 after a group of developers bent on increasing bitcoin's block size limit prepared a code change, known as a hard fork. As a result, the bitcoin blockchain and cryptocurrency split in two. Owners of BTC at the time of the fork found themselves in possession of an equal number of BCH.