On August 1, 2017, the popular cryptocurrency, Bitcoin split into two derivative currencies, Bitcoin Cash (BCH) and Bitcoin Classic (BTC). The origin of the split can be tracked back to 2010. During that time, as a spam control measure, a one megabyte per 10 minutes limit was introduced. The mechanism worked smoothly because the value of Bitcoin was low and trading was limited.
However, once the popularity of the Bitcoin grown exponentially and become hugely popular, the one-megabyte limit started being a burden. Miners, users, and companies differ how to solve the problem. One side wanted the limit raised to match the growing demand of Bitcoin. Others argued that a rapidly growing Bitcoin will shift to corporate control and will get centralized.
After years of argument, the Bitcoin Cash advocates decided to create a split of the Bitcoin ledger and see how the market reacts. The original Bitcoin Classic hold onto it one-megabyte limit, while the Bitcoin Cash increased the limit to eight megabytes and introduced a new ticket system, BCC, also called BCH.
This book on Bitcoin Hard fork will give you all the necessary information you need to get familiar with Bitcoin split and Bcash.