# Rarity A natural progression of this numbering system is that people have begun to seek rare and desirable satoshis now that they can be individually tracked and transferred. Ordinal theorists can decide for themselves which sats are most prized, but certain periodic Bitcoin events lend themselves to a rarity hierarchy: * Blocks: A new one roughly every 10 minutes * Difficulty Adjustments: Every 2016 blocks (\~2 weeks) * Halvings: Every 210,000 blocks (\~4 years) * Cycles: Every 6 halvings (\~24 years), with halving and difficulty adjusting aligning This yields the following rarity tiers: * Common: Any non-first satoshi of a block * Uncommon: First satoshi of each block * Rare: First satoshi of each difficulty period * Epic: First satoshi of each halving epoch * Legendary: First satoshi of each cycle * Mythic: First satoshi of the genesis block The degree notation visually denotes an ordinal's rarity: ``` A°B′C″D‴ │ │ │ ╰─ Index of sat in the block │ │ ╰─── Index of block in difficulty adjustment period │ ╰───── Index of block in halving epoch ╰─────── Cycle, numbered starting from 0 ``` Some examples: 1°1′1″1‴ - Common 1°1′1″0‴ - Uncommon 1°1′0″0‴ - Rare 1°0′1″0‴ - Epic 1°0′0″0‴ - Legendary 0°0′0″0‴ - Mythic --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://book.runesterminal.io/2.-origins/ordinal-theory-ordinals/rarity.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.