The BLAKE2b Fork’s Early Issuance Ran About Nine Times Bitcoin’s Target Pace.

Correction — 6 September 2026

This September 3 story misstated the activation sequence and drew comparisons the evidence did not support. September 2 was Wednesday, not Tuesday. The August 8 split began during mandatory signaling, not enforcement of all BIP110 data restrictions. The nine-times calculation covers August 30 to September 2, not just the period after a difficulty reset; it describes faster issuance in calendar time, not an increased eventual subsidy cap. We have removed the cross-algorithm difficulty ratio, which cannot establish relative security or attack cost.

We also wrongly treated Knots' description of its minority chain slowing down as a claim about the majority SHA-256d chain. We have corrected that framing, distinguished the minority chain's last SHA-256d block from the chains' shared history, and withdrawn unsupported blanket claims about wallet compatibility and CPU-mining promises. An unverified exchange-pricing anecdote has been removed. These errors came from conflating distinct activation stages, chains and measurement windows, and extending source observations beyond what they established. The headline and deck now identify the historical window. The original publication date and URL are retained.Corrections

Update — 7 September 2026

Luke Dashjr replied to our correction with a wider window. Measured from the 8 August split at height 961,632 to the 2 September observation at 965,704, the minority chain found 4,073 blocks in 24.7 days against about 3,550 expected at Bitcoin’s ten-minute target, roughly 15 percent above pace; his figures, 4,074 against 3,600 over nearly four weeks, put it at 13 percent. Both calculations are correct for their windows. The difference is that the chain produced eight SHA-256d blocks in the 21.4 days before the algorithm change and 4,064 BLAKE2b blocks in the 77 hours after it. The nine-times figure describes the second period; the whole-life figure averages the stall and the burst.21

Bitcoin Knots 29.4.1 became a final release at 19:02 UTC on Wednesday, September 2. Its release notes cast the majority SHA-256d chain as an altcoin and the minority chain continued under BLAKE2b as Bitcoin. That is the developers' position in a disputed chain-identity argument, not a technical finding this report adopts.09

The early mining record presents a narrower question. How quickly did the BLAKE2b chain issue coins, and what changed for someone holding keys? The observations below are from the August 30–September 2 window. They are not a live estimate of today's pace.

Three chains and different rules

BIP110 was a proposed temporary tightening of consensus rules around arbitrary data. Its deployment specified mandatory bit-4 signaling for blocks 961,632–963,647, mandatory lock-in at 963,648, and full activation at 965,664. During mandatory signaling, a non-signaling block was rejected; that was not yet enforcement of all the proposed transaction restrictions. The BIP repository marked the proposal Closed on August 9, citing a split with stalled mining.17

The later BLAKE2b hard fork was a separate change. The project FAQ places its first block at 961,640 on August 30, with temporary data restrictions beginning at that point. It describes the algorithm change as permanent and the data limits as expiring when the previous block's median time past reaches September 1, 2027, 00:00 UTC. Keeping those limits afterward would require a further choice of rules, not a continuation of BIP110's old signaling schedule.18

Bitcoin Purity is another chain. Its project site describes a separate fork retaining SHA-256d with altered difficulty and permanent data restrictions. Its block heights must not be mistaken for the BLAKE2b chain's progress.10

What the nine-times figure measures

SG's retained September 2 source record from BLAKE2b Miner reported height 965,704 at 11:24 UTC. The first BLAKE2b block, 961,640, was timestamped August 30 at 06:14 UTC. The site's operator also mines the chain, so this is an interested source, not an SG full-node measurement.11

Those observations span 4,064 height increments over 77.2 hours: about 1,264 blocks per day, or 8.8 times Bitcoin's ten-minute target of 144 daily blocks. At a 3.125-coin subsidy, the increments imply about 12,700 coins of block subsidy, excluding fees. This compares the observed window with a target schedule, not a claim that the other chain produced exactly 144 blocks each day.

The window includes the first two difficulty adjustments; it does not begin at a reset. Faster blocks bring subsidy forward in calendar time. They do not, by themselves, increase the eventual subsidy cap: the tagged implementation still halves the subsidy by height, with a mainnet interval of 210,000 blocks.1920

Raw difficulty numbers for SHA-256d and BLAKE2b are not a ratio of economic attack costs. A security comparison would need evidence about compatible hardware, available and rentable hashpower, ownership concentration, and the cost of sustaining an attack. Our original numerical comparison did not provide that evidence.

What slowed, and what supporters argue

The release's description of a network brought “to a crawl” refers to the minority chain its authors recognize as Bitcoin. Showing normal block production on the majority SHA-256d chain does not refute that description. They are different chains with different outcomes.09

BIP110's affirmative case is that miners receive transaction fees while node operators bear continuing costs associated with carrying arbitrary data. That is an argument about who pays to verify and operate the network, and it deserves examination. The proposal also acknowledges trade-offs for some advanced Taproot uses. Neither a chain's name nor its early issuance rate settles whether the restrictions improve ordinary users' ability to run nodes.17

The project explicitly supports purpose-built BLAKE2b mining hardware. ASIC participation therefore does not, on its own, disprove the project's stated design. SG has not measured mining profitability or the distribution of control among those machines.18

What a holder actually risks

Holding coins does not require claiming a forked asset or switching software. Spending is a separate matter. The chains share history from before the August split, so some ordinary signed transactions can remain valid on more than one chain. The minority chain's last SHA-256d block at 961,639 is not the point through which it shares all history with the majority chain.

Murch's July 6 explanation warned about replay during the proposed mandatory-signaling split. Bitcoin Optech reported minority-chain replay attacks on August 28. Both accounts predate the final BLAKE2b release and are context for the risk, not audits of that release.1206

The project's newer SIGHASH_UNIFIED format provides opt-in, per-signature protection against replay onto a chain that does not implement that format; ordinary signatures are not automatically protected. SG has not independently tested this protection or established a complete list of compatible wallets. The release itself warns that third-party software may require upgrades.1809

Lightning adds counterparty and monitoring risks. Start9's pre-BLAKE2b operator guide warned about transactions being replayed and revoked channel states appearing on a chain an operator was not watching. It is historical context, not a current coin-splitting or channel-closing procedure.13

An exchange credit, wallet label or claim service is not proof that spending is safe. Never give a seed phrase to a service offering to claim forked coins. This report does not recommend a wallet, an exchange or a transaction procedure.

What remains unproven

The early record supports a finding of faster calendar-time issuance in a specified window. It does not establish today's pace, an increased supply cap, comparative attack costs or universal wallet compatibility.

The ordinary-user test still requires work: measured node costs, usable payments, reliable self-custody and an honest account of mining and wallet trade-offs. Fair coverage means testing that case without treating either the project's branding or its critics' conclusions as proof.