> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/wiki/blocks-and-the-blockchain/blockchain/re-org.md). # Re-org When Miners find conflicting blocks that each build on the same chaintip, two or more competing chaintips emerge. At a certain point, a Miner will discover a new block that results in a clear elongation of one of the competing chaintips beyond the others resulting in the emergence of a clear longest proof of work chain. At this point, any Miner working on a shorter chaintip will cease trying to build on the failed extension and migrate their work to the longest tip. Part of this process is the removal of transactions from the now defunct blocks and the construction and validation of the [Merkle tree](https://en.wikipedia.org/wiki/Merkle_tree) for the blocks in the new longest chaintip. This is called a re-org, as it is the re-organisation of all transactions in the now orphaned chaintip, to match the ordering of the new longest proof of work chain. These are common events (approximately one in every 300 blocks results in a race) and are an important part of the Nakamoto Consensus mechanism. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://hub.bsvblockchain.org/wiki/blocks-and-the-blockchain/blockchain/re-org.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.