In 2015, the world's most decentralized currency ended up in the hands of two warring clans, and no one could hit the "reboot" button. A technical dispute over block size turned into an information war with censorship, DDoS attacks, and accusations of corporate conspiracy—with the future of money at stake.
Bitcoin was suffocating. 7 transactions per second—that was the network's ceiling with 1 MB blocks, which Satoshi Nakamoto had implemented in 2010 as temporary spam protection. By 2015, this limit had become a noose: fees shot up to $50 per transaction, confirmations stretched into hours, and users fled to competitors. Visa processed 24,000 transactions per second. Bitcoin couldn't cut it as a payment system—it was a museum exhibit with a "do not touch" sign.
Mike Hearn and Gavin Andresen proposed a simple solution: increase blocks to 8 MB. On August 15, 2015, they launched Bitcoin XT with BIP 101—an alternative client implementation where block size could grow exponentially to 8 GB by 2036. The logic was ironclad: internet bandwidth is growing, hard drives are getting cheaper, miners will manage. But Gregory Maxwell and the Bitcoin Core team saw a threat: every megabyte of block size means gigabytes of blockchain archive per year, inaccessible to home nodes. Decentralization versus scalability. Security versus convenience.
Roger Ver, a Bitcoin evangelist with hundreds of millions in capital, sided with big blocks. His argument was pragmatic: if the network can't process a $3 coffee, it's useless as currency. Jihan Wu, owner of the largest mining pool Antpool, backed Ver—miners were losing money on stuck transactions. On the other side of the barricades—Bitcoin Core developers, funded by Blockstream, which had received investments from AXA Strategic Ventures and PwC. Ver publicly accused them of corporate capture: why increase blocks when you can funnel transactions into your own Lightning Network solution running on top of the main chain?
The dispute wasn't solved with code. It was solved in chats, on forums, and in negotiating rooms where technical arguments mixed with suspicions, and suspicions with personal animosity.
The r/bitcoin forum on Reddit was the community's main venue—500,000 subscribers, daily discussions, the rallying point for consensus. Theymos, a moderator since 2010, also owned Bitcointalk.org and controlled the information space. When the Bitcoin XT campaign began in August 2015, Theymos declared it "an attack on Bitcoin" and banned discussion of alternative clients. Posts were deleted, users were banned, threads were closed with the label "altcoin promotion."
Big block supporters created an alternative subreddit r/btc and began collecting evidence of censorship—screenshots of deleted threads, ban logs, discussion archives. The "proof of censorship" project documented hundreds of moderation cases: mentioning Bitcoin XT was equated with altcoin advertising, criticizing Core with trolling. Bitcointalk suffered DDoS attacks during critical votes, the forum crashed for hours precisely when miners were trying to coordinate their position.
Mike Hearn couldn't take it anymore. On January 14, 2016, he published the post "The resolution of the Bitcoin experiment" and left the project. His diagnosis was harsh: the network has been captured by a group of developers controlling the Bitcoin Core repository; censorship on forums has turned discussion into an echo chamber; miners who should be defending decentralization are afraid to go against Core for fear of "social attack." Hearn sold all his bitcoins and went to work at bank R3. For small block supporters, this became proof of correctness—the traitor fled to the bankers. For Ver—proof that ideological control kills engineers.
Gavin Andresen, former lead developer and Satoshi's successor, lost access to the Core repository after supporting Bitcoin XT. Formally—due to "account compromise" after meeting with Craig Wright, who claimed to be Satoshi. Informally—due to politics. The man to whom Nakamoto handed over the code was out of the game.
February 2016, Hong Kong. In a hotel conference room gathered 50 representatives of mining pools and Core developers—a last attempt to avoid a split. Miners controlled 90% of hashrate and demanded block size increase. Core proposed a deal: first activate Segregated Witness (SegWit)—a technology that moves transaction signatures outside the block and increases throughput to the equivalent of 1.7 MB, and in a few months discuss a hard fork to 2 MB.
Both sides signed the Hong Kong Roundtable Agreement, but the deal was built on sand. SegWit required a soft fork—a backward-compatible upgrade that doesn't split the network. Increasing to 2 MB—a hard fork where old nodes become incompatible. Core promised to "explore" a hard fork but didn't guarantee it. Miners agreed because they saw no alternative.
By October 2016, it became clear: Core wasn't going to do a hard fork. Bitcoin Unlimited—a third alternative implementation proposed by the community—allowed miners to choose block size themselves through voting. The idea of free market versus central planning. Core called it "an attack on consensus." Ver invested money in promoting Unlimited, funding conferences and YouTube channels. Amaury Séchet, a developer from France, began work on Bitcoin ABC—a client that would become the foundation for the final split.
May 23, 2017, New York, Consensus conference. 58 companies—exchanges, mining pools, payment processors—signed the New York Agreement (NYA). A new compromise: activate SegWit through BIP 91, and three months later increase the block to 2 MB through a hard fork SegWit2x (B2X). Signatories represented 83.28% of hashrate and billions of dollars in capitalization. Core refused to participate—they weren't invited to the negotiations.
If miners could vote with power, users responded with code. BIP 148—User-Activated Soft Fork—proposed a radical scenario: on August 1, 2017, nodes supporting BIP 148 would start rejecting blocks without SegWit support, even if miners were against it. This could split the network into two chains, but small block supporters went all in. Their logic: if 15-20% of nodes support UASF, exchanges and wallets will be forced to choose which chain to consider the "real Bitcoin." And the market will determine the choice.
Jihan Wu and miners found themselves trapped. Ignore UASF—get two chains and chaos. Support SegWit—betray the idea of big blocks. The NYA compromise collapsed before it began: on July 21, miners activated BIP 91, starting the SegWit activation process to prevent the split from BIP 148. On August 24, SegWit went live on block 481824. Users won the battle against miners, proving that decentralization isn't just about hashrate.
But on August 1, three weeks before SegWit activation, the inevitable happened. Bitcoin ABC, Séchet's client, executed a hard fork on block 478558, creating Bitcoin Cash with 8 MB blocks without SegWit. This wasn't an "attack"—it was a split along ideological lines. Ver, Wu, some miners and users who had been demanding big blocks for years got their Bitcoin. Bitcoin Core remained on 1 MB blocks with SegWit, opening the road to Lightning Network.
November 2017 was supposed to be the culmination. Block 494784—the moment when SegWit2x would increase blocks to 2 MB, fulfilling the NYA promise. 58 companies were preparing for the hard fork, exchanges were developing protocols for listing two chains, miners were accumulating power. Core launched an information campaign: "NO2X"—hashtag, petitions, statements. Bitcoin.org published a warning: B2X is an attack, don't update your nodes.
November 8, six days before the planned fork, Mike Belshe, CEO of BitGo and NYA initiator, published a letter: "While we continue to believe in the need for block size increase, it has become clear that we don't have sufficient consensus. Continuing would divide the community and harm Bitcoin's growth. We are canceling the plan to activate the SegWit2x hard fork." Six key NYA participants signed.
The market responded instantly: bitcoin price rose 10% in 24 hours, reaching $7,800. Bitcoin Cash fell. Ver called the cancellation "capitulation to censorship and propaganda." Core supporters celebrated the victory of nodes over corporations. SegWit2x died before being born, but consensus remained dead too. Formally, the war ended. Ideologically—it continues to this day: r/bitcoin and r/btc remain parallel universes where the same events are interpreted as betrayal or triumph of decentralization, and Bitcoin and Bitcoin Cash exist as monuments to the impossibility of reaching agreement.