After the BCH hard fork, we compiled a Bitcoin "fork list" for you

Original source: Bitcoin Magazine

Original translation: BitcoinM

On the evening of November 15, the Bitcoin Cash (BCH) hard fork was successfully completed, giving birth to two chains, BCHA and BCHN. In fact, Bitcoin Cash itself is also a chain forked from the original Bitcoin. As the "king of cryptocurrency", how many forks does Bitcoin have? Now, let's review it with everyone.

First of all, we need to understand a concept, namely: What is the so-called fork?

The word “fork” can be a bit confusing. In fact, there are many different types of “forks” in the cryptocurrency and blockchain world, and their meanings vary. Specifically, they include:

Codebase fork

A codebase fork is a "code copy" of a software implementation. A codebase fork usually refers to an adjustment to the original codebase. In Bitcoin, a codebase fork can be fully compatible with the Bitcoin protocol, or it can result in an unexpected blockchain fork or the establishment of a completely new cryptocurrency.

Blockchain Fork

A blockchain fork occurs when a blockchain splits into two versions of its transaction history, which can happen for a variety of reasons, some expected and some unexpected, depending on the circumstances. A blockchain fork can result in a variety of outcomes, from a single orphaned block to an entirely new cryptocurrency.

Hard Fork

A hard fork is a protocol upgrade where some protocol rules may be relaxed or removed after a hard fork. If all users upgrade, then a hard fork will not cause the blockchain to split. In the case of Bitcoin in particular, some people argue that unless all users upgrade, the "upgraded" protocol should not be called a hard fork at all, but rather a "new cryptocurrency" or "forked coin."

Soft Fork

A soft fork is also a protocol upgrade whose main function is to strengthen or add protocol rules. A soft fork upgrade may cause the blockchain to fork, but the party with the majority of computing power will enforce the soft fork, thereby ensuring that the network follows the same transaction history. Generally speaking, a miner-activated soft fork (MASF) is triggered by computing power, while a user-activated soft fork (UASF) is triggered by users.

Gray Area

Although the above four fork terms and definitions cover the types of "forks" currently available in the cryptocurrency market, the real environment is actually very complicated. For example, the difference between hard forks and soft forks does not seem to be obvious, and the crypto community sometimes cannot even tell which fork should be considered a protocol upgrade. Not only that, in some cases, industry experts also have different opinions on the type of "fork", some of which are politically motivated, and some want to rewrite transaction history, which makes Bitcoin forks even more confusing.

Next, let’s get down to business and see how many forks there are in Bitcoin?

Satoshi Nakamoto officially launched Bitcoin in 2009 when he released the first version of the Bitcoin codebase. Bitcoin was then known as “Bitcoin” (or more precisely, the first version of Bitcoin should be called “Bitcoin 0.1.0”). The descendants of this codebase were renamed “Bitcoin Core” and are sometimes also referred to as the “Satoshi client”.

Regular Bitcoin blockchain forks

When two or more miners find a valid block at the same time, the Bitcoin blockchain will fork into two branches. According to the Bitcoin fork design, these blockchain branches will be resolved as soon as one branch chain becomes longer, at which time the shorter branch chain will be abandoned ("orphaned"). Even today, this happens frequently.

Bitcoin's first soft fork

The first soft fork protocol upgrade of Bitcoin disabled the protocol function OP_RETURN. Technically, this was a user-activated soft fork, or UASF. However, in the early stages of Bitcoin, only Satoshi Nakamoto "actually controlled" the Bitcoin protocol rules, so this upgrade did not cause a blockchain fork.

Bitcoin's first hard fork

The first hard fork protocol upgrade of Bitcoin added a new feature OP_NOP, and this fork was actually decided by Satoshi Nakamoto himself. However, not everyone thinks that this upgrade is a true hard fork, because this fork did not lead to a blockchain split.

Bitcoin blockchain has no intention of forking

An unintentional blockchain fork occurs when different parts of the Bitcoin network see different transaction histories and the situation cannot be resolved automatically. This type of blockchain fork is usually caused by a software bug or other technical problem and is one of the biggest short-term glitches Bitcoin can encounter. Fortunately, unintentional blockchain forks have only occurred two or three times in Bitcoin's history, and each time they were resolved smoothly through community coordination without causing much damage.

Bitcoin Knots

Bitcoin Knots is the first example of a fork of the Bitcoin Core codebase, which is a "code copy" of a software implementation and therefore does not cause a blockchain split. In fact, Bitcoin Knots is fully compatible with Bitcoin Core - it just provides different functionality.

Libbitcoin

Libbitcoin is an example of a fork that fully reproduces the Bitcoin protocol in a different codebase that is not a fork of the Bitcoin Core codebase, but is also fully compatible with Bitcoin Core.

The first miner-activated soft fork (MASF) in Bitcoin history

The P2SH upgrade can be said to be the first miner-activated soft fork (MASF) in Bitcoin’s history. Although subsequent miner-activated soft forks used a purer, hashrate-based upgrade mechanism, none of them caused a blockchain fork.

BIP148 Client

Another example of a fork of the Bitcoin Core codebase is the BIP148 client, which forced a user-activated soft fork to activate the "Segregated Witness" protocol upgrade and may now be incompatible with Bitcoin Core and other Bitcoin clients.

Bitcoin ABC

Bitcoin ABC is another example of a fork of the Bitcoin Core codebase, but Bitcoin ABC forked to a degree that ensured it would be incompatible with Bitcoin Core and other Bitcoin clients at some point in time.

Bitcoin ABC officially separated from Bitcoin and created "Bitcoin Cash"

On August 1, 2017, Bitcoin ABC was no longer compatible with Bitcoin Core and other Bitcoin clients. Since then, Bitcoin ABC has created a new cryptocurrency called "Bitcoin Cash", or Bitcoin Cash (Chain News Note: Bitcoin Cash has also experienced several forks since then, including the BCHN and BCHA chains that were forked on November 15, 2020).

BTC1

BTC1 is also a code base fork of Bitcoin Core, which is also incompatible with Bitcoin Core and other Bitcoin clients. But BTC1 has a specific purpose, which is to deploy a hard fork upgrade for the new Bitcoin protocol "Segwit2x". (In other words, the goal of BTC1 is to get all Bitcoin users to switch to the Segwit2x protocol and regard the protocol as the so-called "real Bitcoin.")

The first user-activated soft fork (UASF) in Bitcoin history

The BIP148 client fork did not actually receive enough community support because it wanted to break away from Bitcoin to create a new cryptocurrency, but only a handful of miners eventually upgraded to the corresponding system, so the BIP148 client is still compatible with other Bitcoin clients. Many people believe that this protocol upgrade is the first "real" user-activated soft fork (UASF)

, because the fork was not decided by developers, but was born out of a grassroots user movement.

Bitcoin Clashic

Bitcoin Clashic is a brand new version of Bitcoin ABC, designed to upgrade to the Bitcoin Cash protocol through a hard fork. In fact, most Bitcoin Cash users have completed the upgrade and recognized the new protocol name as "Bitcoin Cash". However, there is still a small number of users who choose to continue using the first version of the Bitcoin Cash protocol (which the mainstream crypto community has always regarded as a joke), and these users named this forked cryptocurrency: "Bitcoin Clashic".

Bitcoin Core Sq

In early 2018, most of the Bitcoin Clashic community adopted a codebase fork of the Bitcoin Clashic client, called Bitcoin Core Sq, which was incompatible with the existing Bitcoin Clashic client, resulting in the creation of a completely new cryptocurrency, but the Bitcoin Clashic community deliberately named it "Bitcoin Core". It is important to note that Bitcoin Core Sq and/or the real Bitcoin Core software client, and/or the real Bitcoin Core cryptocurrency, and/or the real Bitcoin protocol are not compatible. Bitcoin Clashic has been around for a while, but is now completely abandoned (largely because the community still supports Bitcoin Core).

Segwit2x Failed

Due to various reasons, almost no one in the crypto community adopted BTC1, resulting in BTC1 not only being unable to "upgrade" the Bitcoin protocol, but also being unable to continue to exist as a new cryptocurrency in the market.

Bitcoin Gold, Bitcoin Diamond, and dozens of other Bitcoin forks

After Bitcoin ABC successfully created Bitcoin Cash through a blockchain fork, the crypto community saw a precedent for success, and many Bitcoin "forks" began to appear. In fact, the reason why Bitcoin Cash was able to fork successfully was mainly due to the long-term disagreements in the Bitcoin community, but most of the "forks" that appeared later were for forking for the sake of forking. They just thought that forking was a "good way" to create another new cryptocurrency, nothing more.

Bitcoin SV

Bitcoin Satoshi’s Vision (Bitcoin SV) is a codebase fork of Bitcoin ABC, but the cryptocurrency has made adjustments to the protocol designed to ensure that it will be incompatible with the Bitcoin Cash protocol at some point in the future.

Bitcoin ABC and Bitcoin SV part ways

In 2018, due to the growing disagreements within the Bitcoin Cash community, Bitcoin ABC and Bitcoin SV decided to separate from the existing Bitcoin Cash protocol. Although sometimes referred to as "Bitcoin Cash ABC", Bitcoin ABC is superior to Bitcoin SV in almost every aspect, so the "Bitcoin Cash" that the crypto community now refers to is actually Bitcoin ABC, and Bitcoin SV during the fork process that year is still referred to as "Bitcoin SV" by the crypto community.

Bitcoin Dark

Bitcoin Dark is a codebase fork of Bitcoin Core that launched a cryptocurrency of the same name: Bitcoin Dark. Like Litecoin and many other altcoins, Bitcoin Dark adjusted its codebase to be completely incompatible with the Bitcoin protocol from the beginning. Therefore, Bitcoin Dark is a brand new cryptocurrency and cannot be considered a blockchain fork, but it just happens to have "Bitcoin" in its name. Today, Bitcoin Dark seems to no longer exist.