Bitcoin Cash is both a cryptocurrency and the decentralized blockchain network on which it transacts. You might also see Bitcoin Cash referred to as its ticker symbol, BCH. As a fork of Bitcoin, or BTC, Bitcoin Cash is very similar to the original cryptocurrency. The most significant difference is the amount of transaction data the individual blocks of each network can store.
Bitcoin Cash was created in 2017 following years of disagreement within the original Bitcoin community. Increasing Bitcoin adoption led to a rising number of transactions competing for the same limited block space. When there are too many transactions to fit in a single block, miners prioritize those including the highest fees. Rising transaction fees made Bitcoin less viable for smaller payments.
Opinions were split on how best to scale Bitcoin. Some reasoned that raising the block size would increase overall capacity — reducing the need to outbid other users' transaction fees. Others argued that this would lead to network centralization, since node operators would need more expensive hardware to store the entire blockchain. Instead, they advocated scaling using layers above the main chain.
In August 2017, those Bitcoin miners favoring larger blocks introduced the change. It split the network, and all wallets holding BTC at the time received an equal number of the new BCH. Since then, Bitcoin Cash has continued to increase the maximum block size. As of January 2021, Bitcoin Cash blocks can be up to 32 MB.
Bitcoin Cash plans to continue increasing block sizes gradually. Updates are scheduled every six months. While most previous hard fork updates have been non-contentious, two that met miner resistance led to the chain splits that created Bitcoin SV in 2018 and Bitcoin Cash ABC in 2020.