Provenance
Proof of Sats is the first collection of physical cards dedicated to exceptional satoshis.
Bitcoin created something no one had anticipated: a currency in which every unit carries a date of birth. We turn them into collectible pieces.
A satoshi
One bitcoin is divided into one hundred million satoshis. The satoshi is the indivisible unit of the network, named after Bitcoin’s anonymous creator.
Twenty-one million bitcoins, one hundred million satoshis each: 2.1 quadrillion satoshis will exist, and not one more. It is the elementary grain of Bitcoin.
For thirteen years, these grains were considered interchangeable. One satoshi was worth one satoshi. That was true from an accounting perspective. Until…
Numbering
In 2022, the Ordinals protocol formalized a simple idea: assigning every satoshi a serial number according to its order of issuance. The first satoshi ever mined carries number 0.
The last will carry number 2,099,999,997,689,999. This numbering changes nothing in Bitcoin. It is not written anywhere, consumes no space, and requires no permission. It simply reads what the ledger has contained since day one.
Each satoshi becomes traceable from its block of origin to the present day. The idea did not originate in 2022. It was already circulating on Bitcoin’s historic forum as early as 2012, discussed by developers who had understood before most that the ledger contained a complete genealogy. It was simply waiting for a protocol. Casascius himself, creator of the first physical coins containing bitcoins, had mentioned this possibility.
Rare and exotic sats
Two forms of rarity coexist.
Protocol rarity follows the rhythms of the network: the first satoshi of each block, each difficulty adjustment, and each halving. These satoshis are known as uncommon, rare, epic, legendary, and mythic. Their rarity is arithmetic: their exact number can be counted.
Exotic rarity is linked to specific events in Bitcoin’s history or to particular numerical properties. These satoshis owe nothing to the protocol and everything to their story. Their rarity cannot be calculated; it has to be told.
In common usage, the term “rare sats” is used for the field as a whole. But precision matters: the satoshis in Series 1 are exotic, not rare in the protocol sense. Their value comes from their origin, not from their position.
Read our article on the difference between ordinal rarity and exotic satoshis.
Series 1: Block 9
Block 9 was mined on January 9, 2009, during the very first days of the network. It is widely attributed to Satoshi Nakamoto, although this has never been cryptographically proven.
What is established, however, is more interesting. Its mining reward was the first ever to be spent. The bitcoins produced by Block 9 are the oldest still in circulation today.
Series 1 is limited to one hundred numbered cards. Each one contains a satoshi from the very first bitcoin of this block, and therefore one of the oldest satoshis still in circulation.
Read our article on the Series 1
A design made by mathematics
We believe the beauty of Bitcoin lies in its mathematics. So we let mathematics do the drawing.
Your satoshi’s serial number is passed through SHA-256, the cryptographic algorithm at the heart of Bitcoin. The resulting hash is then derived into a guilloché pattern: number of bands, radius ratios, rotation angles, palette. Everything is determined by the number. Change a single digit in the input, and the output becomes entirely different and unpredictable.
Guilloché is the engraving technique used on banknotes, stock certificates, and watch dials. Its interwoven patterns are virtually impossible to reproduce by hand. It is a design born from the need to prove authenticity, applied here to an object whose authenticity is already proven elsewhere, on the blockchain.
Each card is therefore unique and carries within it a piece of generative art.
The object
A collectible card.
The front features the guilloché pattern framed by microtext, the satoshi number, its rarity icons, and the card’s serial number.
The back carries the satoshi’s complete data, on-chain verification codes, the cryptographic seal protected by a tamper-evident VOID label, as well as a description of the satoshi.
The entire card is encapsulated in a rigid crystal case, sealed through UV polymerization. It cannot be opened without destroying the enclosure.
Each card comes with a signed Certificate of Authenticity.
Manufacturing
The cryptographic elements are produced on a workstation physically isolated from any network. Printing is carried out through a direct wired connection. No copy is retained after production.
The complete ten-step protocol is publicly documented.
Don’t trust, verify
Every serial number in this collection can be independently verified on the blockchain, right now and before any purchase.
Recovering the satoshi
A Proof of Sats card is designed to remain intact. Removing the satoshi means separating it from the collectible that was created to preserve it.
But ownership also means being able to move it.
For this reason, we developed Pos Recovery, an open-source tool designed specifically for Proof of Sats cards. Rather than sweeping the card’s private key into a conventional wallet (which could cause part of the card’s UTXO, including the rare sat, to be consumed as mining fees) Pos Recovery transfers the entire card UTXO to an Xverse Ordinals address, while fees are paid from a separate input.
The tool runs locally on your computer and its source code is publicly available on github for inspection.