Bitcoin forks are defined variantly as changes in the protocol of the bitcoin network or as the situations that occur "when two or more blocks have the same block height". A fork influences the validity of the rules. Forks are typically conducted in order to add new features to a blockchain, to reverse the effects of hacking or catastrophic bugs. Forks require consensus to be resolved or else a permanent split emerges.
All four software clients attempt to increase transaction capacity of the network. The majority hash power did not begin to use these clients. Therefore there was no consensus to change the rules.
Hard forks splitting bitcoin are created via changes of the blockchain rules, sharing a transaction history with bitcoin up to a certain time and date. The first hard fork splitting bitcoin happened on 1 August 2017, resulting in the creation of Bitcoin Cash. A list of hard forks splitting bitcoin by date and/or block follows: