Blockchain technology thrives on consensus, but disagreements often lead to dramatic shifts — one of the most impactful being a hard fork. Bitcoin Cash (BCH), born from a hard fork itself, has experienced multiple splits and ideological battles throughout its history. This article explores the pivotal moments in BCH’s evolution, explains the mechanics of hard forks, and demystifies replay protection — a critical security feature during chain splits.
What Is a Hard Fork?
A hard fork occurs when a blockchain permanently diverges into two separate chains due to incompatible protocol changes. After the upgrade, nodes running the old software can no longer validate blocks created by upgraded nodes, resulting in two parallel blockchains.
Key characteristics of a hard fork:
- No backward compatibility: All participants must upgrade to the new rules.
- Dual chains emerge: One follows the new rules; the other continues under the old consensus.
- Consensus deadline: A specific block height or time triggers the split, with non-upgraded nodes remaining on the legacy chain.
Hard forks aren’t inherently good or bad — they reflect differing visions within a decentralized community. Some see them as innovation; others view them as fragmentation. Let’s examine key events that shaped BCH and the broader crypto landscape.
Major Blockchain Fork Events
The Bitcoin Chain Split of 2013
In March 2013, Bitcoin faced an unexpected hard fork caused by a database upgrade in Bitcoin Qt 0.8.0. This version introduced LevelDB, which allowed larger blocks — over 800KB — that older clients (Qt 0.7) couldn’t process.
At block height 225430, two chains formed:
- One chain accepted large blocks (from upgraded nodes).
- The other rejected them (from legacy nodes).
The community resolved the issue by reverting to Qt 0.7, effectively abandoning the longer chain. While not intentional, this event demonstrated how software incompatibility could split a blockchain — a lesson later applied during planned upgrades.
👉 Discover how blockchain networks handle critical upgrades securely.
The DAO Incident and Ethereum's Split
In June 2016, a vulnerability in The DAO, a decentralized autonomous organization built on Ethereum, allowed hackers to siphon off around $60 million worth of ETH. In response, the Ethereum Foundation led a hard fork at block 1920000 to reverse the theft by redirecting funds to a recovery address.
This created two chains:
- Ethereum (ETH): The forked chain with reversed transactions.
- Ethereum Classic (ETC): The original chain preserving immutability.
Critics argued that reversing transactions violated blockchain’s core principle: immutability. Because no replay protection was implemented, transactions on one chain were valid on the other, leading to cross-chain losses — especially for exchanges handling both assets.
This case highlighted the importance of replay protection in future forks.
The Birth of Bitcoin Cash (2017)
As Bitcoin struggled with high fees and slow confirmations due to its 1MB block limit, debate intensified over scalability. Two camps emerged:
- Small-block supporters: Favored off-chain solutions like the Lightning Network.
- Big-block advocates: Pushed for on-chain scaling via larger blocks.
No consensus was reached, culminating in a hard fork on August 1, 2017, at block 478558. Bitcoin Cash (BCH) launched with an 8MB block size, aiming to restore Bitcoin’s original peer-to-peer cash vision.
Crucially, BCH developers implemented SIGHASH_FORKID, a unique transaction signature type, and modified locking scripts to ensure replay protection. This meant users could safely transact on either BTC or BCH without accidentally spending coins on both chains.
Exchanges distributed BCH to BTC holders via airdrop, creating widespread interest in fork-based asset creation. However, many subsequent BTC forks — such as BTG and BCD — lacked long-term utility and faded away.
The 2018 BCH Civil War: ABC vs. SV
By 2018, internal tensions within the BCH community escalated into what’s known as the “hash war.” Two factions emerged:
- Bitcoin ABC (led by nChain): Advocated evolving BCH into a smart contract platform with moderate block sizes (32MB).
- Bitcoin SV (led by Craig Wright): Promoted massive block scaling (up to 128MB) and adherence to Satoshi Nakamoto’s original protocol.
With no agreement on development direction — including script opcodes and funding models — a hard fork became inevitable.
On November 15, 2018, BCH split into:
- BCHABC (later simply BCH)
- Bitcoin SV (BSV)
This time, no replay protection was enforced, causing confusion for exchanges and users. Many platforms had to manually distinguish between chains using heuristics or temporary ticker symbols (e.g., BAB).
After a fierce mining competition, BCHABC gained dominant hash power and retained the BCH ticker. BSV stabilized independently. Exchanges like Binance and Huobi distributed BSV tokens to BCH holders.
👉 Learn how traders navigate volatile chain splits and maximize opportunities.
The 2020 BCHN Takeover: Ideological Warfare
Another contentious upgrade loomed in November 2020, centered around the Infrastructure Funding Plan (IFP) proposed by Bitcoin ABC. The plan allocated 8% of each block reward to fund developer teams — a move critics labeled as centralized taxation.
In opposition, the Bitcoin Cash Node (BCHN) project, backed by developer Andrew Stone and mining pool BTC.com, forked the ABC codebase and removed IFP.
As both clients prepared for the upgrade:
- ABC included IFP.
- BCHN excluded it.
Since the two versions were incompatible, another split was imminent — unless one side gained overwhelming support.
Replay Protection in Action
Developers confirmed that replay protection would be active, ensuring safe separation between chains. Techniques like "colored UTXO" were used:
- Pre-fork UTXOs were spent twice — once on each chain.
- These “seed” outputs marked future transactions as chain-specific.
- Any transaction referencing an invalid input on one chain would be rejected, preventing cross-chain replay.
Platforms like Matrixport adopted this method to safeguard user funds during the transition.
Who Gets to Be “BCH”? Exchange Policies Diverge
With naming rights at stake, exchanges adopted different strategies:
Price-Based Naming
Exchanges like CoinEx and OKX decided to assign the BCH ticker to whichever chain had higher market value post-fork. The losing chain received a new symbol and was airdropped 1:1.
Consensus-Based Recognition
Huobi, Binance, and Bithumb Global pledged to wait for community consensus before deciding which chain deserved the BCH name.
Pro-BCHN Stance
Coinbase and Kraken openly supported BCHN:
- Coinbase refused to support ABC’s forked token.
- Kraken designated BCHN as “BCH” and would only list ABC’s version if it gained ≥10% network hash rate (under ticker BAB).
BTC.com, a major mining pool, also endorsed BCHN after extensive testing, signaling strong industry backing.
Frequently Asked Questions
Q: What triggers a hard fork?
A: A hard fork happens when there's a fundamental change to a blockchain’s protocol that isn't backward compatible, requiring all nodes to upgrade.
Q: Why is replay protection important?
A: Without it, a transaction on one chain can be duplicated on the other, potentially leading to unintended losses across both networks.
Q: How do exchanges handle forked coins?
A: Most take snapshots of user balances before the fork and distribute new tokens proportionally. Policies vary on naming and listing based on price or community support.
Q: Can I profit from a hard fork?
A: Yes — if you hold the original coin before the split, you typically receive an equal amount of the new coin (a "fork airdrop"). But always check exchange policies.
Q: Does every fork create valuable new coins?
A: Not necessarily. Long-term value depends on adoption, development activity, and real-world use — many forks fade due to lack of utility.
Q: Should I keep my BCH in a wallet or exchange during a fork?
A: Exchanges often pause deposits/withdrawals during forks but handle airdrops automatically. For full control, use a private wallet — but ensure you understand replay risks.
👉 Stay ahead of upcoming crypto forks with real-time market insights.
Final Thoughts
The story of Bitcoin Cash is more than technical upgrades — it's a reflection of decentralization in action. From its birth out of Bitcoin’s scalability debate to internal wars over funding and ideology, BCH’s journey underscores how vision, governance, and community shape digital currencies.
Each fork brings challenges — technical complexity, user risk, market uncertainty — but also opportunities for innovation and growth. As blockchain evolves, understanding these dynamics becomes essential for investors, developers, and enthusiasts alike.
Whether you're watching for potential airdrops or studying consensus mechanisms, staying informed is your best tool in navigating the ever-changing crypto landscape.