While Bitmain is one of the most important companies in the Bitcoin industry, many people are unaware that the company operates with two CEOs. Public communications over the years have often come from Jihan Wu, while less is known about Micree Zhan, who is more deeply involved in the technical side of the business.
In a recent interview with CoinJournal, Zhan discussed Segregated Witness (SegWit), Bitcoin Unlimited (BU), the role of miners within the Bitcoin ecosystem, and other topics.
CoinJournal: Many people in the Bitcoin community outside China don’t know much about you. What is your background and how did you become involved in Bitcoin?
Micree Zhan: I am an electronics engineer. Before co-founding Bitmain, I ran a startup focused on integrated circuit design. In 2013, Jihan introduced me to Bitcoin. After spending about two hours learning its basic concept, I quickly recognized its potential and knew it was the right direction to pursue.
CJ: What is your primary role at Bitmain? I’ve heard you are the company’s technical expert.
MZ: That’s correct. I focus on product development and oversee Bitmain’s engineering teams.
CJ: What are your thoughts on Bitcoin Unlimited’s emergent consensus concept? Should miners activate this change, and should users support it?
MZ: Bitcoin’s block size is approaching the 1 MB limit, and several proposals have been introduced to address this constraint. Bitcoin Unlimited’s emergent consensus is one promising approach. Support for emergent consensus in the community has been growing. I believe emergent consensus is more straightforward and more practical than SegWit, and that many miners will choose to activate it.
I also think users should support BU because it provides an alternative implementation of the Bitcoin protocol. Bitcoin’s core value is its unique ledger—its consensus—not a single, exclusive implementation maintained by Core.
CJ: Did the recently mined invalid block by Bitcoin.com, caused by a Bitcoin Unlimited bug, change your view on BU or emergent consensus?
MZ: No. From an engineer’s perspective, no software is completely free of bugs. Fortunately, the incident resulted in only a small loss. Supporting multiple, high-quality implementations strengthens the network: a bug in one implementation will affect some nodes but not all, and nodes can switch to other implementations if needed. When bugs occur, timely leadership and responsiveness from developers matter greatly. In this case, I believe BU developers responded well, just as Core developers have handled bugs in the past.
CJ: What do you think about Bitcoin Core’s Segregated Witness proposal? Should miners activate it and should users support it?
MZ: SegWit is a very clever idea that would benefit Bitcoin. However, it is somewhat complex, and the community needs more time for careful evaluation and testing. I don’t believe it is safe to activate SegWit right now.
CJ: Are there block size proposals outside of Bitcoin Unlimited and SegWit that you support?
MZ: At the moment, I prefer Bitcoin Unlimited.
CJ: What about proposals to increase the block size using extension blocks? Do you support them, or do they carry complexities similar to SegWit?
MZ: Many worthwhile scaling proposals have been suggested, including extension blocks. Technically, extension blocks are an elegant solution. However, many proposals lose momentum for reasons unrelated to technical merit.
CJ: There’s an ongoing debate about miners’ role in Bitcoin. Some argue miners should follow user preferences, while others say miners should lead protocol changes. What is your perspective?
MZ: I don’t think miners should bear the responsibility for moral or political decisions about protocol direction. The primary concern for miners is the economics of mining. Mining is a smart mechanism for generating bitcoins and maintaining network stability: more miners and higher difficulty generally make the network more secure. As long as mining remains economically viable and attracts more participants, Bitcoin’s security will improve. In 2016, we launched the open-source mining pool BTC.com to make mining more accessible and efficient.
CJ: If miners shouldn’t make moral or protocol decisions, shouldn’t they nonetheless signal for SegWit, given that many parts of the ecosystem (Coinbase, BTCC, Blockchain.info, Xapo, etc.) appear prepared for it?
MZ: Bitcoin is a complex system with many stakeholders—users, miners, exchanges, developers—each with different incentives. Following Satoshi’s vision, miners should profit from mining. Miners invest significant capital and resources to operate, and they will select solutions like SegWit or BU based on what aligns with their interests: increasing block capacity, encouraging broader adoption, or capturing transaction fees.
CJ: Any final thoughts about Bitmain or Bitcoin?
MZ: At Bitmain, we will continue working to make Bitcoin healthier and stronger.
Note: The sequence of questions in this interview has been rearranged for clarity.