Chain split occurs when a blockchain diverges into two separate chains because of differences in protocols or rules. This often happens due to disputes among the community or developers about the future direction of the blockchain.When a chain split occurs, one group may choose to upgrade the software to introduce new features or fix perceived issues, while another group may prefer the existing version. This division can lead to two competing coins, each maintained by its respective community.An example of a chain split is the split between Bitcoin and Bitcoin Cash in 2017. Bitcoin Cash was created to address concerns about transaction speed and costs. Users who held Bitcoin at the time of the split automatically received an equal amount of Bitcoin Cash.Chain splits can create uncertainty and volatility in the market, as they often lead to differing values for the new and original coins. They also highlight the importance of community consensus in decisions about the future of a blockchain.