A #NosChain is a chain of notes. Each note points to the previous note, except for the root.

Each note in the chain can become part of a tamper-proof, auditable, verifiable history by including a "c" tag which points to an on-chain committment.

The root, or genesis, note can point to any utxo, controlled by the users's npub

As the NosChain progresses, so does the utxo progress each transaction spent to self, with a tweak of the previous tx. The tweaked tx contains the hash of the next note in the chain.

In this way chains of notes can live forever in nostr, and also be provably notarized, in a block chain for all time. Useful for history, games, contracts or for storing memories long-term. Furthermore, NosChains could be transferred to another user, or even traded, creating a fun eco system.

This is one free benefit of having nostr npubs and bitcoin taproot use the same key mechanism.