Bitcoin Purity is the latest, and arguably strangest, offshoot of the BIP 110 saga.
Where the BLAKE2b hard fork responded to BIP 110’s failed soft fork activation by launching a clean break — new proof-of-work algorithm, new branding, an openly separate coin — Bitcoin Purity has taken the opposite approach entirely.
Its mainnet went live at 10:00 UTC on August 19, 2026, at block height 961,637, and its stated goal isn’t to become a new asset with a new ticker, but to be the preferred chain for miners and node operators to commit blocks to if they prefer the BIP110 rules and refuse to relay and secure transactions with arbitrary data embedded.
Not much is known about the chain, about who is supporting it, but according to its own site, it “claims the Bitcoin identity” outright, positioning itself not as an alternative to Bitcoin but as an attempt to become the version of Bitcoin that economic consensus eventually settles on.
Why It’s Building on the BIP 110 Extension
Bitcoin Purity’s technical starting point is the Knots/BIP 110 enforcement chain — the minority chain that rejected non-signalling blocks at height 961,632 when the original BIP 110 UASF failed to win over the majority SHA-256d hashrate.
Rather than the Core majority chain that continued at that same height under the old rules, Purity forks specifically from that enforcement branch, inheriting its Reduced Data Temporary Softfork (RDTS) restrictions on arbitrary data: non-empty, non-OP_RETURN scriptPubKeys capped at 34 bytes, OP_RETURN outputs capped at 83 bytes, script elements limited to 256 bytes, Taproot control block depth limited to 7, Taproot annexes made invalid, and OP_IF/OP_NOTIF forbidden inside Tapscript.
The primary selling point in BIP 110’s original design was “temporary” — the restrictions were meant to sunset automatically after roughly a year.
Bitcoin Purity exists to remove that expiry.
As its own materials put it:
“Policy can change. Consensus endures.”
The project’s pitch is that a data-restriction policy sitting in Bitcoin Core’s mempool relay rules can be reversed by a future software release or a change in maintainer sentiment, but a rule enforced at the consensus layer — one that invalidates non-compliant blocks outright — can’t be quietly undone.
Bitcoin Purity hard-codes the RDTS limits permanently into consensus, with no opt-out and no expiry.
What Makes It Different From a Typical Fork?
Most forks go out of their way to make themselves distinguishable from the chain they split from — new ticker, new network magic bytes, new default port, replay protection to stop transactions crossing over accidentally.
Bitcoin Purity deliberately does none of this.
It keeps Bitcoin’s original P2P magic bytes (f9beb4d9), the same default port 8333, identical address formats, transaction serialisation, and sighash logic, the same default data directory and binary names — and it explicitly implements no transaction-level replay protection.
Even its proof-of-work stays on SHA256d, unlike the BLAKE2b fork’s algorithm swap; the only mining-related change is a new difficulty adjustment algorithm, aserti3-1d, ported directly from Bitcoin Cash, with a 24-hour half-life anchored to block 961,632.
The project is explicit that this isn’t an oversight — it’s part of the strategy.
By remaining maximally indistinguishable from Bitcoin at the protocol level, Purity is betting that it can simply wait for “economic consensus” to recognise its ruleset as the legitimate one, rather than engineering a clean, branded split that concedes it’s a separate coin from day one.
What It Means for Bitcoin Holders
For anyone holding Bitcoin, the practical implication is uncomfortably direct: because there’s no replay protection and near-identical protocol parameters, a normal Bitcoin transaction broadcast around the fork boundary can be picked up and confirmed on both the legacy chain and the Purity chain simultaneously.
Anyone interacting with Bitcoin near block 961,632–961,637 without understanding this risks unintentionally transacting on a chain they never chose to engage with, exactly the kind of chaos discussed in any serious breakdown of why replay protection exists in the first place.
Beyond the immediate mechanics, holders are also being asked, implicitly, to pick a side in a dispute over what “Bitcoin” even means going forward — a pure monetary settlement layer with hard data limits, or the status quo chain that continues to allow the OP_RETURN and inscription-style data usage that triggered this entire chain of events.
How Bitcoin Purity Fails?
The most obvious failure mode is the same one that sank the original BIP 110 soft fork: hashrate. Purity keeps SHA256d, which means it competes directly with Bitcoin’s mainchain for the same pool of ASIC miners, without offering any of the higher-value block rewards or transaction fee revenue the dominant chain provides.
Unless a meaningful slice of hashrate voluntarily redirects to Purity’s stratum pools, its chain will struggle to produce blocks reliably, leaving it vulnerable to reorganisation and painfully slow confirmation times — the same stalled-chain problem that plagued the BLAKE2b fork in its early days.
The absence of replay protection is also a double-edged sword.
While it’s framed as a deliberate identity-claiming strategy, it equally means the project inherits none of the clean operational separation that helped chains like Bitcoin Cash and Ethereum Classic establish independent legitimacy after their own splits.
Confused users, frustrated exchanges refusing to list a chain that shares Bitcoin’s exact transaction format, and a general market perception that this is a confusing minority fork rather than “real” Bitcoin could all combine to leave Purity permanently marginalised — technically alive, economically irrelevant.
How Bitcoin Purity Succeeds?
Purity’s theory of victory depends entirely on the “economic consensus” framing being more than marketing language.
If a critical mass of node operators, exchanges, and merchants come to genuinely believe Bitcoin’s data-storage permissiveness is an existential problem, and if that belief translates into real economic activity migrating toward Purity’s ruleset over months or years, the chain’s strategy of maximal protocol similarity actually becomes an advantage rather than a liability — there’s no need to convince anyone to learn new tooling, new address formats, or new wallet software, because everything about interacting with Purity looks identical to interacting with Bitcoin.
Its success ultimately hinges on the same dynamic that decided SegWit’s 2017 UASF: not the loudest chain, but the one that accumulates genuine economic majority support over time. Whether Bitcoin Purity can pull that off against a mainchain with vastly more hashrate, liquidity, and institutional entrenchment remains to be seen.
