Title:
The Story Behind Bitcoin Fork
Bitcoin Cash于2017年8月1日正式从Bitcoin分叉出来，已经过去了两周年。回过头看这两周年的发展，Bitcoin Cash即是成功的，也是失败的。说其成功是在于其仍然有着极其活跃的社区，不断发展的应用，以及稳固的市场地位。说其失败是在于Bitcoin Cash并没有达到大多数支持者对于其超越Bitcoin的预期，以及Bitcoin Cash并没有解决Bitcoin同样面临的一些列治理难题。
It’s been over two years since Bitcoin Cash was officially forked from Bitcoin on August 1, 2017. Looking back, one can say Bitcoin Cash is a success, or failure. Its success lies in its community, which remains extremely active, and solid market position. Yet its failure is owing to that Bitcoin Cash does not meet most supporters’ expectations to surpass Bitcoin, and also that it does not address some of the governance challenges that have been facing Bitcoin as well.
起源
Bitcoin Cash与Bitcoin的分裂来自于比特币的扩容问题，这个问题其实本不该成为问题。这个问题来来源于比特币创造者中本聪在比特币原代码里面留下的一行代码，这行代码限制了比特币区块的大小上限。比特币本质上是一套记账系统，而区块可以理解为是一个账本，是记账的最小单元，每个账本记录着过去大约十分钟比特币网络所有发生的转账交易记录。区块大小上限则限制了比特币网络的交易处理能力。这行代码添加的初衷是防止垃圾交易攻击。在比特币发展的早期，比特币价格还常低的时候，攻击者可以花费很小的代价创造大量的垃圾交易堆满所有节点的硬盘，会将这个极具创新和革命意义的系统扼杀于摇篮。在添加这行代码的时候，有人担心未来会限制比特币网络的发展，中本聪给出的回答也很简单：到时候我们提前把限制调大就可以了。谁会想到，这个简单的扩容问题竟然会导致比特币走向分裂。
The Origin
The split between Bitcoin Cash and Bitcoin came from the capacity scaling of Bitcoin, which, however, shouldn’t have been a problem. The trouble resulted from a line of code left by the Bitcoin creator Nakamoto in the Bitcoin source code, which capped the size of the Bitcoin block. Bitcoin is essentially a set of accounting systems, and a block can be regarded as a book, the smallest unit of accounting, each of which records all of the transfer transactions that have taken place in the Bitcoin network in the past ten minutes. The block size cap limits the transaction processing capabilities of the Bitcoin network. This line of code was originally added to prevent spam transaction attacks. In the early days of Bitcoin's development, when Bitcoin prices were low, attackers could create a large amount of dust transactions to fill the hard drives of all nodes at a small cost, killing this innovative and revolutionary system in the cradle. When adding this line of code, some worried it would limit the development of the Bitcoin network in the future. Nakamoto gave a simple answer: When the day came, they could simply adjust the limit in advance. Who would have thought that this tiny issue of capacity scaling would cause Bitcoin to fork?
比特币扩容问题从2014年开始有人提出，比特币的区块大小在那时候达到了300KB左右，并且维持着指数级的速度上升，按照预测，将在2016年初触达1MB大小上限。比特币的网络是一个去中心化的网络，依赖于一套共识协议来达成共识，对共识协议的修改必须要小心，避免由于不兼容而导致整个网络分叉。如果共识协议收紧，则称为软分叉，老节点无需升级仍然可以正常运行。如果共识协议放开，则成为硬分叉，这种情况下老节点必须升级才可以正常运行。可以简单的理解为软分叉向后兼容，而硬分叉不向后兼容。比如比特币区块大小上限从2MB改为1MB是软分叉，而从1MB改为2MB则是硬分叉，因为大于1MB的区块在老节点上被认为为非法。比特币历史上进行过很多次软分叉升级，还没有出现过硬分叉，因为开发者认为硬分叉升级很可能会导致比特币网络分叉，是一件很危险的事情。而通过提升比特币区块大小上限扩容是一个硬分叉行为，于是这事遇到了很大的阻力。
The capacity scaling of Bitcoin was first raised in 2014 when its block size reached around 300KB and was growing at an exponential rate. According to the forecasts, it would reach the 1MB size limit in early 2016. The decentralized Bitcoin network relies on a set of consensus protocols to reach consensus. So changes to this protocol must be made carefully to avoid the entire network being forked due to incompatibility. If the consensus protocol is tightened, it is called soft fork, and the old node can still run normally without upgrading. If the consensus protocol is loosened, there will be a hard fork. In this case, the old node must be upgraded before running normally. In simple words, soft forks are backward compatible, while hard forks are the opposite. For example, a change in the upper limit of the Bitcoin block size from 2MB to 1MB is a soft fork, and a change from 1MB to 2MB is a hard one, because blocks larger than 1MB are considered illegal on the old node. Bitcoin has undergone many soft fork upgrades in the past, and there has not been a hard fork, because developers believe that hard fork upgrades are likely to cause the Bitcoin network to fork, which is very dangerous. And capacity scaling by increasing the block size of the Bitcoin is a hard fork, which encountered many setbacks.
一
我从2011年就开始关注比特币的发展，到2014年开始的出现的扩容问题时，我认为这是一件很自然要被解决的问题，因此我并没有投入太多精力在这件事情。当时中文社区的讨论主要在一个叫做币科技的论坛上面，我偶尔会关注一下当时社区的讨论。比特币的发展史上有两件事情我一直认为很自然要被解决却很不正常的一直存在的问题，一个就是比特币扩容的问题，还有一个是比特币协议标准化问题。比特币本质上是一套协议，类似于HTTP、Email协议，而不是一套软件。在互联网历史上，凡是成功的协议或者编程语言，都最终被标准化了的，这有利于更多样化的实现。在2018年的时候，我尝试过在Bitcoin Cash上推进协议标准化，也得到了很多人的支持，但最终并没有得到实施，这是后话了。
ONE
I started to pay attention to the development of Bitcoin since 2011. When the issue of capacity scaling was put forward in 2014, I thought it would be solved anyway and did not put too much effort into this matter. At that time, discussion in the Chinese community was mainly on a forum called “Bikeji” (literally Currency Technology). I occasionally had a look at the discussion there. In my opinion, there are two things in the development of Bitcoin that should have been solved yet somehow exist all along: One is the capacity scaling of Bitcoin, and the other is the standardization of the Bitcoin protocol. Bitcoin is essentially a set of protocols, similar to the HTTP and Email protocols, not a set of software. In the history of the Internet, any successful protocol or programming language is finally standardized and it is conducive to more diverse implementation. In 2018, I tried to turbocharge the protocol standardization on Bitcoin Cash, and was supported by many people, but my efforts did not pay off in the end. It is unnecessary to go into details here.
我在2016年之前一直没有参与比特币扩容的话题，那时候更多在潜心研究着交易。一方面我觉得我也影响不了什么，另一方面我认为社区在寻找一个更合适的扩容方式。然后随着2016年上半年比特币区块大小终于达到了1MB的时候，比特币仍然没有扩容，我开始认真关注这个问题，发现社区争论的焦点已经从如何扩容变成要不要扩容，这一下子变成了很严肃的问题。2015年到2016年，比特币开发者社区发生了很多事，比如比特币的扩容版本Bitcoin Classic、Bitcoin XT的诞生，比如香港扩容大会，比如澳本聪的登场以及被称为中本聪继承者也是扩容派领导者的Gavin被夺权等等。比特币核心社区分成了两派，分别是大区块派和小区块派，两派逐渐开始争吵到斗争到决裂，最终以小区块派踢出了全部大区块派的核心开发者，把持了Bitcoin Core代码提交权限而告全面胜利。Bitcoin Core是比特币最主要的一个软件实现，继承自中本聪的原始代码，由于Bitcoin协议并没有完成标准化的，所以Bitcoin Core事实上定义了什么是比特币。
I have not been involved in the topic of Bitcoin capacity scaling until 2016. Before that I was more interested in trading. On one hand, I didn’t think I could make a difference. On the other hand, I believed the community was looking for a better solution. Then, with the Bitcoin block size reaching 1MB in the first half of 2016, Bitcoin still did not have its capacity scaled up. It caught my attention as I found that the focus of debate in the community has changed from how to expand capacity to whether or not to expand it. That was a big issue. From 2015 to 2016 the Bitcoin developer community has undergone a lot, such as Bitcoin Classic, which was the expanded version of Bitcoin, the birth of Bitcoin XT, the capacity scaling conference in Hong Kong, Okamoto’s debut and the step-down of Gavin, known as Nakamoto’s successor and the leader of the capacity-scaling group. The core community was divided into two groups, people in favor of the big blocks and people in favor of the small blocks. The two factions began to argue, fought against each other and later broke up. The last victory went to the small block advocates, who kicked out all the core developers of the big block and grabbed the submission permission of Bitcoin Core code. Bitcoin Core is the most important software implementation of Bitcoin, inheriting the original code from Nakamoto. Since the Bitcoin protocol is not standardized, Bitcoin Core actually defines what Bitcoin is.
我参与到比特币扩容纷争，是因为我在2016年的时候创办了一个比特币矿池：ViaBTC矿池。比特币挖矿是比特币运行的基石，是比特币共识协议的守护者，通过庞大的挖矿网络，构建了一个坚不可摧的比特币网络。在比特币的白皮书里面，也描述了一个通过矿工竞逐最长链而改变共识协议的规则，因此在扩容派开发者失势后，大区块派的支持者将希望放在了矿工身上。如果所有矿工达成一致，一起修改比特币区块大小上限，理论上也是实现扩容的目地的。比特币矿池联系着比特币网络和矿工，因此在扩容事情上，获取了不小的话语权。然后通过联合矿工而实现扩容这条路是非常困难的，比特币网络运行着十几家大大小小的矿池，本身就十分分散。并且比特币的矿工早已不是早期的极客了，而是一群专业矿工，他们进行挖矿并不是因为对比特币有很深入的理解和信仰，而只是一门赚钱的生意。要说服这些人一起进行一件冒险的事情，是何其难啊。然而只要还有一线希望，还是要去尝试。
I got involved in the dispute over Bitcoin capacity scaling when I started a Bitcoin mining pool in 2016: ViaBTC. Bitcoin mining is the cornerstone of Bitcoin operation and the guardian of the Bitcoin Consensus Protocol that builds an indestructible Bitcoin network through a vast mining network. The Bitcoin whitepaper also sets out a rule that changes the consensus protocol with miners competing for the longest chain. Therefore, after the developers supporting capacity scaling failed, supporters of the big block turned to miners. If all miners agree to modify the upper limit of the Bitcoin block size, things could work out theoretically. The Bitcoin mining pool is a link between the Bitcoin network and the miners, so it has considerable say in the expansion. Things could be rather difficult by uniting the miners as there were a dozen of mining pools, big or small, scattering around the Bitcoin network. And Bitcoin miners were no longer early geeks, but a group of professional miners who, without deep understanding or belief in Bitcoin, took it as a profitable business. How hard was it to convince these people to take risks together! However, as long as there was still a glimmer of hope, I got to try.
矿工也需要合适的比特币软件来完成扩容，在2015年的时候，涌现了很多比特币扩容的方案和实现，包括上面提到的Bitcoin Classic和Bitcoin XT，还有一个很有意思的实现是Bitcoin Unlimited. Bitcoin Unlimited提出了一种通过矿工投票的方式动态的调整区块大小的方案，这可以避免后续再次硬分叉扩容。当时在推广自己的矿池的时候，一些人在Twitter上问我是否支持Bitcoin Unlimited，我回答说正在关注和测试，这引起了很多人的关注，也结交了很多朋友。吴忌寒，最大的矿机厂商比特大陆的掌舵者，中国最早的比特币投资者和布道者之一，也是我的投资人和创业导师。Roger Ver, 最早的比特币投资者，投资了大量比特币初创公司而被称为比特币耶稣，也是著名的自由主义斗士。他们都是大区块的核心支持者，给了我莫大的鼓励和支持。2016年10月份的时候参加了在米兰的比特币开发者大会，然而整个大会却不允许对当下最紧迫的扩容问题进行讨论。原以为只有在中国才有的言论管制出现在了最为倡导自由的比特币社区当中，真是莫大的讽刺。参加完大会后，我就在自己矿池的区块标记中添加了Bitcoin Unlimited的标识，并公开宣布支持Bitcoin Unlimited，这引起了轩然大波。
Miners also need the right Bitcoin software for capacity scaling. In 2015, there were quite a few Bitcoin expansion plans and implementations, including the Bitcoin Classic and Bitcoin XT mentioned above, and the interesting Bitcoin Unlimited. Bitcoin Unlimited proposed a scheme to dynamically adjust the block size by means of a miner voting, which can avoid subsequent hard-fork expansion. When promoting my own mining pool, I was asked on Twitter if I supported Bitcoin Unlimited. My reply that I was paying attention and testing it brought me a lot of followers and friends: Wu Jihan, head of Bitmain, the largest mining machine manufacturer, and one of the earliest Bitcoin investors and promoters in China, is my investor and entrepreneurial mentor; Roger Ver, the first Bitcoin investor who has invested in a large number of Bitcoin startups, is known as the Bitcoin Jesus and is also a famous liberal fighter. They are both the core supporters of the big block and have encouraged me a lot. In October 2016, I attended the Bitcoin Developer Conference in Milan, but discussion of the most urgent expansion issue was not allowed there. It was a great irony that speech control, which I thought was exclusive to China, took place in the Bitcoin community which should have been the biggest advocate for freedom. Back from the conference, I added the logo of Bitcoin Unlimited to the blocks mined in my mining pool and publicly voiced my support for Bitcoin Unlimited. That caused an uproar.
平心而论，我实际上是比特币拥堵的受益者。我们知道比特币挖矿的收益包括两部分：新币奖励和交易手续费，随着比特币挖矿奖励的逐步减半，新币奖励逐渐降低，而交易手续费预期将随着比特币得到普及而提高。在2016年之前，比特币交易手续费占比微乎其微，此时比特币矿池默认的潜规则是交易手续费收入归矿池所有，是不分给矿工的。而随着2016年初比特币开始拥堵，比特币交易手续费逐步变得可观，我首创了PPS+的收益分配模式，首次将交易手续费也额外的分给了矿工，增加了矿工的收入，获得了很多客户的信任，后续其它矿池也开始跟进，成为了事实上的标准。另外，我也首创的推出比特币交易加速器产品，用户可以提交比特币交易ID，我们矿池会优先打包这个交易，并且规定每个小时可以免费为前100条交易加速。这个产品随着比特币拥堵问题的加剧开始病毒式的传播，每当有人抱怨他们的比特币交易迟迟没有得到确认时，都会有人丢给我们交易加速期的链接。很快，每小时100条免费额度变成了秒杀，这个产品给我们带来了巨大的流量和品牌的传播。
To be honest, I am the beneficiary of jammed network traffic. We know that Bitcoin mining revenue includes two parts: Block mining rewards and transaction fees. As the Bitcoin mining rewards are gradually halved and reduced, yet transaction fees are expected to increase with the popularity of Bitcoin. Before 2016, Bitcoin transaction fees accounted for a negligible proportion. At this time, it remains the unspoken default in the Bitcoin mining pool that the transaction fees were owned by the mining pool, not the miners. With the jammed network traffic in early 2016, Bitcoin transaction fees have gradually become considerable. Then I pioneered the PPS+ revenue distribution model. For the first time, the transaction fee was additionally distributed to miners which increased their income, and won the trust of many customers. Other mining pools have followed suit, and the model has become the de facto standard. In addition, I launched the first Bitcoin Transaction Accelerator, where users can submit Bitcoin tTXIDs and our mining pool will prioritize their transactions. It is also stipulated that the first 100 transactions can be accelerated for free every hour. This product went viral as the network traffic got increasingly jammed. Whenever someone complained about the long wait for the confirmation of their Bitcoin transactions, someone would give him/her a link to our transaction accelerator. The 100 free credits per hour became the rage at the market before long, and this product brought us tremendous traffic and brand reputation.
但是，早期比特币的参与者和投资者都是对比特币怀着巨大的热忱的，实在不愿意看到比特币变得这么难用。在早几年，微软、戴尔等巨头纷纷开始支持比特币支付，而随着比特币拥堵的加剧，比特币逐渐变得不再可靠，反而开始纷纷取消对比特币的支持。如果只是从精明的商人的角度，支持扩容和分叉是无利可图的，甚至会背负骂名。但如果不是因为信仰，谁会去做这些傻事呢。很多人喜欢阴谋论，但我从来对和我意见相反的人保持最大的善意，大家只是理念向左罢了。至于谁对谁错，只能交给历史去评判。
However, early Bitcoin participants and investors were extremely enthusiastic about Bitcoin, and the last thing they want to see was that Bitcoin becomes so difficult to use. Years earlier, giants such as Microsoft and Dell began to support Bitcoin payment, and, as the network traffic got jammed and Bitcoin became less reliable, they took back their support. In the eyes of a savvy businessman, it is unprofitable to support capacity scaling and fork, which may even result in notoriety. Who would do these thankless things if it were not for faith? Many people are interested in conspiracy theories, but I have always kept the best kindness to those who disagree with me. We just stick to the totally different beliefs. Only history will tell the right from wrong.
我开始积极的联络着各大矿池，希望他们一起支持BU。矿工在这件事情上几乎是毫无立场的，像局外人一样，主要还是靠矿池经营者决策。虽然希望渺茫，但必须一试。逐渐开始有一些矿池被我说服，开始宣布支持BU。我帮助Roger Ver建立了Bitcoin.com矿池，他也旗帜鲜明的开始支持BU。江卓尔也创办了自己的比特币矿池，也是大区块的主要支持者。特别是比特大陆最终也公开宣布支持BU，一下子让BU获得了超过50%算力的支持，BU节点的数量也大幅上升。似乎再争取一下，BU就要成功了。但就在这紧要关头，BU连续出现了几个严重的BUG，每次都导致大面积节点掉线。这下子Core支持者开始狂欢，开始疯狂的诋毁大区块派，中立者也逐步开始不信任BU的技术能力，开始倒向Core。
I started to actively contact the major mining pools in the hope that they would support BU (Bitcoin Unlimited) together. Miners almost have no position in this matter. Like the outsiders, they generally rely on the decision of the mining pool operators. I got to try even for a glimmer of hope. As time went by, some mining pools were convinced and began to voice support for BU. I helped Roger Ver build Bitcoin.com, and later he supported BU in a clear-cut manner. Jiang Zhuo’er also founded his own Bitcoin mining pool, who is also a major supporter of the big block. In particular, Bitmain’s public expression of support gave BU more than 50% of hashrates, and significantly increased the number of BU nodes. It seemed that success was just around the corner. But at this critical moment, BU suffered several serious bugs, causing large-area nodes to drop offline every time. As a result, Core supporters flew over the moon and madly smeared the big block, and the neutrals began to doubt BU’s technology and turned to Core’s side.
二
扩容问题开始陷入僵局。扩容问题的本质并不在于通过什么方式扩容？是否要硬分叉？是否支持SegWit？是否支持闪电网络？而是是否要扩容的问题。扩容派也提出了多个软分叉的扩容方案，但都被Core拒绝了。SegWit解决的并不是扩容问题，而是解决了比特币一直存在的交易延展性问题，并且为未来升级比特币协议提供了更简便的方式。闪电网络和扩容更不是冲突的，甚至闪电网络也需要扩容才能真正的运行。扩容问题的本质是双方对比特币和去中心化的理解不一致。大区块派认为比特币是一个支付网络，其价值来源于交易，交易越多，价值越高；而小区块派认为比特币是价值存储网络，不需要特别频繁的交易，当前的区块大小已经足够使用了。大区块派认为比特币得到越多的采用，越多人的支持，会变得越去中心化，就算区块增大，也会有足够多的人负担的起运行节点的费用；而小区块派认为增大区块会增大比特币运行成本，会导致比特币变得中心化。可笑的是，小区块派认为一笔比特币转账交易需要支付超过100美金的手续费是合理的，而运行比特币节点的硬件设备超过100美金却是不合理的。
TWO
Capacity scaling fell into a deadlock. Its root lies not in what way to scale up capacity, whether or not to hard fork, or whether it supports SegWit and lightning network. It is a question of whether or not to expand. The expansion advocates also proposed a number of soft fork plans, all rejected by Bitcoin Core team. SegWit solves more the problem of transaction extensibility that Bitcoin has always had, than the capacity scaling, and provides an easier way to upgrade the Bitcoin protocol in the future. The lightning network and capacity scaling are not conflicting, and the lightning network even needs capacity scaling for real operation. The core of the dispute over capacity scaling lies in the inconsistency of understanding in Bitcoin and decentralization between the two sides. The big block supporters think Bitcoin is a payment network, and its value comes from transaction: The more transactions, the higher the value; and the small block supporters hold that Bitcoin is a value storage network which does not require too frequent transactions, and thus the current block size is enough. According to the former, the more Bitcoin is adopted, the more supporters and the more decentralized it will be. And there will be enough people to bear the cost of running the node even if someday blocks become larger; on the contrary, the other side believes that a larger block will increase the running cost and thus cause Bitcoin to become centralized. Ironically, they think it reasonable to pay more than $100 for a Bitcoin transfer yet unreasonable to spend over $100 on the hardware running Bitcoin nodes.
由于Bitcoin Core开发团队历史以来积累的声誉和路径依赖问题，加上随着牛市的来临，大量新入场的投资者对比特币并不十分了解，希望以稳定为主，因此Core主导的小区块逐渐占了上风，BU彻底落败。比特币扩容之争持续了接近三年一直没有分叉的原因就是因为没有人希望看到比特币分裂，所有人都惧怕分裂，惧怕分裂导致的价格崩盘。甚至有人提出用算力杀死小链，确保比特币不分叉的方案。殊不知，链可以杀死，但意识形态杀不死。比特币分叉的背后是意识形态的分叉，只要有人支持，一个币总是可以以某种形式存活下去。
Owing to the reputation accumulated by the Bitcoin Core development team in the past and path dependence, and with the advent of the bull market where a large number of new investors are not very familiar with Bitcoin and prefer to be stable, Core-led blocks took the upper hand, and BU completely lost. The reason for the dispute over capacity scaling that continued for nearly three years without any fork is that no one wanted it. Everyone was afraid of the price collapse caused by the fork. Some people even proposed to use hashrates to kill small chains and ensure that Bitcoin does not fork. They have no idea that the chain can be killed, but the ideology can't. Behind the Bitcoin fork is the polarization of ideology. As long as a coin is supported, it can always survive in some form.
我逐渐意识到试图说服所有人达成共识已经是不可能的，社区里面开始有人提出小算力分叉的想法，我开始倾向于支持通过小算力分叉来开创一条独自发展的道路。我和其它人分享了这个观点，大多数人还是不希望比特币分裂，还是希望通过大算力分叉的方式实现比特币扩容升级，以确保比特币不发生分裂。不过好在小算力分叉并不需要得到其它人的支持就可以干，小算力分叉出一个新币已经是大区块派唯一可选的方向了。
I gradually realized that it was impossible to convince everyone to reach a consensus. Some people in the community began to propose small-hashrate fork. I tended to support the independent development in this way. I shared my view with others. Still, most people didn't want a fork but capacity scaling by big-hashrate fork to ensure that Bitcoin did not fork. Fortunately, small-hashrate fork can be done without others’ support, and it seemed to be the only feasible direction for the big-block supporters.
这个时候大多数大区块派还寄希望于纽约共识达成的2MB加Segwit方案，我很明确的指出了这条路是走不通的。虽然这个会议得到了90%以上的算力和绝大多数交易所、钱包服务商的支持，但矿工只是一群乌合之众罢了，无法有效的达成一致。虽然绝大部分矿池都打上了支持纽约共识的标记，但谁又能保证他们真的都运行了新的版本呢？贸然行动的矿工大概率会面临损失，这类似于囚徒悖论，矿工最有利的选择还是运行老的版本。并且新的软件版本只有一个Github代码库，正式的官网和下载地址都没有，怎么得到公众的信任呢？
Even at this time, most of the big block advocates still placed their hope on the Segwit+2MB plan reached by the New York Consensus. I made it clear that this road was not going to work. Although this conference was recognized by more than 90% of hashrates and most exchanges and wallet service providers, the miners were merely a gathering of crowds who could not effectively reach an agreement. Despite their declaration for the New York Consensus, who can guarantee that they are actually running a new version? Reckless miners are at a great risk of losses, somewhat alike to the Prisoner Paradox, so the old version remains the most advantageous choice for them. Moreover, the new software version has only one Github code base with no official website or download address. How can it be trusted by the public?
小寒也做了两手准备，在支持纽约共识的同时，把小算力分叉当作为备份方案。我们一开始希望BU能够开发出可用的版本，但他们迟迟没能开发出稳定的版本。这个时候一个新的开发团队Bitcoin ABC突然横空出世，迅速的开完成了一个高质量的可用版本。当时Core团队核心成员发起了UASF(用户激活软分叉）运动，准备强制在2017年8月1日强制激活Segwit，于是我们也选择在8月1日这天开启UAHF（用户激活硬分叉）。新的实现在比特币的基础上把区块大小上限提升到8MB，并且修改了难度调整算法，使用一种称为EDA（紧密难度调整）。比特币的区块难度规则是每2016个区块（大约两周）调整一次的，如果新的链沿用这个规则的话，矿工会付出巨大的沉没成本，很可能会导致这条链胎死腹中。通过EDA，挖矿难度会在出快速度变慢时迅速的降低，以吸引矿工。关于新链的名字，我们各自想了好几个，最后选择了小寒提出的Bitcoin Cash，简称BCC。这个名字取自比特币白皮书的标题：Bitcoin: A Peer-to-Peer Electronic Cash System，也准确的表达了比特币成为支付系统的理想。由于没注意到一个也叫BCC的海外项目BitConnect，名字重复了，为了避免误解，所以后来改名为了BCH。
Wu Jihan has got a Plan B. While supporting the New York Consensus, he took the small-hashrate fork as a backup. At first we expected BU to develop a usable version, but they failed. Then a new development team, Bitcoin ABC, came out and quickly unveiled a high-quality version. At that time, the core members of the Core team launched the UASF (User Activated Soft Fork) campaign, and planned to force the activation of SegWit on August 1, 2017. So we decided to activate UAHF (User Activated Hard Fork) on the same day. We raised the block size limit to 8MB on the current basis and modified the difficulty adjustment algorithm using EDA (Emergency Difficulty Adjustment). Bitcoin's block difficulty rule is adjusted for every 2016 blocks (about every two weeks). If the new chain followed this rule, miners would pay a huge sunk cost, which was likely to kill the chain in the cradle. With EDA, the difficulty of mining would fall rapidly when the mining speed slowed down to attract miners. Each of us came up with several names for the new chain, and we finally chose Bitcoin Cash, proposed by Wu Jihan, or BCH for short. This name derived from the title of the Bitcoin white paper: Bitcoin: A Peer-to-Peer Electronic Cash System, which accurately expressed the vision to make Bitcoin a payment system.
三
临近分叉的时候ViaBTC已经不仅仅是一家矿池了，在大约两个月前我们上线了ViaBTC交易所，支持人民币与比特币的交易。我们一方面在矿池上提前开放了Bitcoin Cash挖矿的选择，选择Bitcoin Cash的矿工会在8月1号的时候自动进行Bitcoin Cash的挖矿；另一方面在交易所开放了Bitcoin Cash期货的交易，用户可以充值BTC进来，以冻结BTC的方式释放出BCC进行提前交易。于是Bitcoin Cahs还没有真正诞生的时候，提前有了算力和价格的支持，一下子获得了全球很多人的关注。
THREE
When the Bitcoin was about to fork, ViaBTC was more than a mining pool. We launched the ViaBTC exchange about two months ago to support exchange between RMB and Bitcoin. On one hand, we opened Bitcoin Cash mining options in advance, and the mining union that selected Bitcoin Cash would automatically mine Bitcoin Cash on August 1; Meanwhile, we supported Bitcoin Cash futures pairs on the exchange so users could deposit BTC and release the BCH by freezing BTC for early trading. With the support of hashrates and price in advance even before Bitcoin Cash was officially online, it had attracted the attention of many people around the world.
在分叉前还有一个插曲，我们发现Bitcoin ABC的实现并没有做交易防重放处理。什么意思呢，如果没有做交易防重放处理的话，分叉后用户在支付BCC的同时很可能也会支付BTC，这是非常危险的，也会给用户带来很大的麻烦，很有可能会导致分叉失败。在和开发者紧急沟通后，他们添加了防重放处理，这会让Bitcoin Cash变得和现有的基础设施不兼容，但为了活下去，也只能这么做。具体分叉生效时间是北京时间8月1日晚上8点，由于Bitcoin Cash硬分叉规则要求第一个分叉区块大小必须大于1MB，因此我提前准备了很多交易，用来塞满第一个区块。我也把我精心准备的一句话“Welcome to the world, Shuya Yang!”放入到了区块。这句话一语双关，一方面庆祝我马上要出世的女儿，另一方面也是庆祝Bitcoin Cash的诞生。晚上8点到了，一下子涌入了很多算力来挖Bitcoin Cash, 但却迟迟没有出块。挖矿过程更像是摇筛子，是一个概率游戏，是否能挖到矿，不仅仅看期望值，也要看运气。第一个块迟迟没有出来，我一再的检查系统，确保没有任何错误，焦虑的等待着。直到6个多小时后，一直到凌晨2点，第一个区块终于诞生了，由ViaBTC挖出。Bitcoin Cash自此诞生了！几分钟后，另外一个区块也由另一个矿池挖出，原来还有人也在默默的支持Bitcoin Cash。我们能抢到第一个区块，实属运气。
There was another episode before the fork: We found anti-replay processing was missing in the implementation of Bitcoin ABC. What does that mean? Without the anti-replay processing, users may pay BTC while paying BCH after fork, which is very dangerous and could result in great losses for users and failure in fork. After urgent communication with developers, they added anti-replay processing. Incompatible as Bitcoin Cash may be with the existing infrastructure as a result, that was the only one choice for its survival.
The fork took effect at 8:00 pm on August 1st, Beijing time. Since the size of the first fork block must be greater than 1MB according to Bitcoin Cash’s hard fork rule, I prepared a lot of transactions in advance to fill the first block. I also put a sentence that I elaborately prepared into it: "Welcome to the world, Shuya Yang!" It was to celebrate the birth of my daughter and also Bitcoin Cash. At 8 o'clock in the evening, a lot of hashrates poured in for Bitcoin Cash, but no block was yet generated. The mining process was more like playing dice. It is a probabilistic game. Your gains depend on luck as well as your expectation. The first block took so long to come that I checked the system again and again to make sure there were no errors. I was waiting in upset. It was not until more 2 am, after over six hours, that the first block was mined, by ViaBTC. That marked the birth of Bitcoin Cash! A few minutes later, another block was also mined by another mining pool. Some people were still supporting Bitcoin Cash in silence. We were so lucky to grab the first block.
Bitcoin Cash的成功分叉引来了大量人的关注，交易所的注册用户猛增，分叉第二天仅一天的用户注册量就超过了1万，这超过了我们上线两个月以来总注册量的十倍还多。好在我们系统一开始就是按照海量用户的目标进行设计的，在面临业务的极速增长时毫无压力。当时团队也只有十个人左右，财务是压力最大的部门，负责用户的法币充值提现业务，由于业务量增长太快，我们也受到了银行的特殊关注。交易所的成交量也急剧放大，每天的成交额达到了数亿人民币。如果不是马上来临的九四被迫关停，ViaBTC很可能会迅速成长为全球最大的数字货币交易所之一。
The successful fork of Bitcoin Cash caused a sensation among crypto-enthusiasts. On the day after the hard fork alone, the number of newly registered user on ViaBTC exchange soared to over 10,000, more than tenfold that of the first two months combined. Yet we were not caught unprepared as our system was designed for users in large numbers. At that time our team consisted of only less than a dozen of people. The rocketing growth of business not only posed a big pressure on our finance department which was in charge of handling the deposit and withdrawal of fiat currency on the platform, but also drew the close attention of the banks. Nevertheless, there was a rapid increase in BCH transaction, rising to tens of millions of dollars per day. Were it not for the shutdown following the ban initiated by the government on September 4th 2017, ViaBTC would have quickly grown into one of the largest crypto exchanges in the world.
四
Bitcoin Cash已经成为了不可忽视的力量，很多交易所被用户倒逼被迫向用户发放Bitcoin Cash资产并开放交易市场，迅速的，Bitcoin Cash得到了几乎所有交易所的支持。大量大区块支持者开始转向支持Bitcoin Cash，在纽约共识彻底流产后，Roger Ver等大区块派也全面转向了对Bitcoin Cash的支持。自此，比特币正式分裂了。比特币的价格也并没有像以前所有人担心的那样崩盘，只是在8月1号分叉后，价格进行了短暂下跌除权后，继续恢复上涨。
FOUR
As Bitcoin Cash emerged as a key player in the market, users began to call for crypto-exchanges to consider the listing and trading of BCH. It didn’t take long for Bitcoin Cash to win over most, if not all, of them. At the same time, Bitcoin Cash also witnessed a surge in the number of its believers who were against the block size limit. The collapse of New York Agreement also prompted Roger Ver and other proponents of increasing the block size to convert to Bitcoin Cash. Henceforth Bitcoin split. Unlike what people expected, its price didn’t crash. Instead, it resumed growth after a short dip in August 1st when the fork took place.
Bitcoin Cash早期的EDA策略也非常成功，确保了其可以在小算力支持的情况下成功存活下来。不过也带来了一个意料之外的副作用，EDA只会在出块速度变慢是调低难度，却没有调高难度的机制，这造成了Bitcoin Cash网络出块速度非常不稳定。另外，在难度快速下降后，Bitcoin Cash挖矿的收益远远高于挖比特币，这吸引了大量的矿工进行套利。我们也迅速的在矿池上面推出了根据收益智能切换挖矿币种的功能，吸引了大量的客户。由于EDA机制的缺陷，Bitcoin Cash迅速在11月份又进行了一次硬分叉，将EDA升级为DAA，新的算法采用逐块难度调整设计，可以保证Bitcoin Cash网络更稳定的运行。
The early EDA algorithm was a huge success. It helped our platform survive even without the support of the majority of miners, but came with an unexpected side effect. Under EDA, the mining difficulty would be lowered when the speed of block production slowed but there was no way to adjust it back up. This led to unstable block intervals on the network. However the good thing was that the reduction in difficulty made mining on Bitcoin Cash much more profitable than on Bitcoin, thus attracting a great number of users. As a response, we swiftly rolled out a new smart functionality on mining pools that allowed miners to switch between cryptocurrencies to maximize payoffs. To fix the problem of EDA, Bitcoin Cash did another hard fork in November to shift from EDA to DAA. The new algorithm aimed to enable stable network operation through block-by-block adjustment of mining difficulty.
尾声
Bitcoin Cash虽然是扩容版本的比特币，但失去了比特币的一切，不仅仅是名字，也包括了所有的生态基础设施，一切要从零开始建设。比特币虽然激活了SegWit，但扩容效果正如所料的那样根本起到任何作用。比特币变得越来越堵，高峰的时候一笔比特币转账费用需要接近1000美金，大量的应用开始转向其它竞争链。但比特币这个名字积攒了比特币运行多年带来的信用，比特币价值主要是由投资价值构成，而非使用价值。Bitcoin Cash还太年轻，在短暂的冲击到兑比特币0.5的历史高位后，价格开始一路下滑。比特币仍然凝聚着整个数字货币最大的共识，大而不倒。
The End
Despite being the scalable version of Bitcoin, Bitcoin Cash has to start from the scratch - New name, new infrastructure and everything. As expected, SegWit implemented by Bitcoin was powerless to rein in the worsening network traffic jam. At peak time, it took as much as 1000 dollars to make a transaction on Bitcoin when the network was busy. This, inevitably, resulted in an exodus of DApps to alternative chains. Nevertheless, the name of Bitcoin embodies the the network’s reputation of safe operation over the years. Its real value lies in being an asset to invest rather than a currency to spend. Of course, Bitcoin Cash is still young. Peaking shortly at 0.5 BTC per BCH, the price of BCH has been dropping ever since. The biggest consensus in the crypto community remains and will continue to be Bitcoin.
在整个比特币扩容和分叉事件中，也暴露出来比特币事实上上是由开发者掌握的，而非矿工掌握的。Bitcoin Cash同样如此，矿工决策从来没有真正的生效过。Bitcoin ABC团队成为了新的Core，他们开始主导Bitcoin Cash每隔半年的硬分叉升级。
All the disputes surrounding the scalability and fork of Bitcoin also reveal that it is developers, not miners, that hold sway over the network. Though operated under a decentralized method, its governance heavily relies on the centralized decisions. So does Bitcoin Cash. The decisions made by its miners have never really come into effect. Regardless of the denial by Bitcoin ABC team, they are in fact the new Core of Bitcoin Cash and Now that Bitcoin ABC is the new core, they are responsible for leading the hard fork every six months on Bitcoin Cash. The decentralized governance broke down under the PoW consensus yet it might be to some degree realized under the PoS consensus.
Bitcoin Cash在2018年又因为理念问题再次面临分裂问题，整个社区元气大伤。加上Bitcoin Cash的核心支持者比特大陆在2018年低遇到一些列问题，Bitcoin Cash价格跌到了历史的最谷底。但即便如此，Bitcoin Cash仍然保持着强大的生命力，是比特币最有力的竞争者。
The split of Bitcoin Cash arising from divergence of views in 2018 took a heavy toll on BCH community. The reason that caused the split was so ridiculous and I will save it for another article. Compounding the issue was the challenges that Bitmain, one of Bitcoin Cash’s core supporters, encountered at the end of the same year. As a result, the price of BCH fell to a record low.
Nevertheless, Bitcoin Cash is still the biggest competitor to Bitcoin, as it enjoys huge potential to grow.
Bitcoin Cash在过去两年诞生了非常多的应用，在不断的创造着属于自己的生态。而比特币扩容问题一直没有解决，寄予厚望的闪电网络也从来没有真正得到过普及。在未来牛市来临的时候，比特币必然将面临更为严峻的拥堵问题，而Bitcoin Cash做为大区块版本的比特币，届时也必将大放异彩！
The past two years has seen the emergence of a myriad of DApps on Bitcoin Cash that contribute to a healthy ecosystem. However, scaling remains the problem awaiting solution for Bitcoin and its much-anticipated lightening network has yet to be adopted on a mass scale. By the time the market turns bullish, we are bound to see a heavily congested Bitcoin like never before, yet Bitcoin Cash, the scalable version of Bitcoin, will be able to realize its true potential.
At the beginning of 2018, ViaBTC exchange was reborn on CoinEx. CoinEx was the first exchange to use Bitcoin Cash as the base currency, and it also received investment and support from Bitmain. CoinEx has become a mature exchange covering more than 80 mainstream cryptocurrency and supports a variety of derivatives including margin trading, perpetual contract, options trading, and futures trading. In addition, CoinEx Chain will be launched soon, built for DEX (decentralized exchange). We hope that CoinEx DEX will become a decentralized platform where anyone could issue, list and trade token freely. In the ecosystem of CoinEx, CET (CoinEx Token) is the native built-in token of CoinEx Chain. We will continue to improve CoinEx ecosystem and enhance the value of CET.
The future is here and the present might the worst of times, but it might also be the best of times
备注：本文的中文作者为ViaBTC和CoinEx CEO杨海坡，译者为丹尼。