Chapter 1. Bitcoin made simple
Every number in the book has a source. To keep the book short, the notes live here instead of in print. Each source is listed with the section of the book it supports and the words it backs up, in the order they appear in the chapter. Web addresses are links; a page may have moved since the date shown.
The six-minute answer: five ideas: “About 20.1 million existed as of September 2026”
Circulating supply, calculated from block height 969,192 (Blockstream and BlockCypher block explorers, September 29, 2026): about 20.09 million bitcoin of a maximum of 21 million. Because amounts are rounded to whole satoshis, the true maximum is a hair under 21 million, about 20,999,999.98.
The six-minute answer: five ideas: “The founder left in 2011 and has not been heard from since” · Who is Satoshi Nakamoto: “wrote to a developer that he had “moved on to other things” and disappeared”
Satoshi Nakamoto, email to developer Mike Hearn, April 23, 2011 (“I’ve moved on to other things. It’s in good hands with Gavin and everyone.”), as shared by Hearn and reported in Vice (Motherboard), August 11, 2017; last public forum post, bitcointalk.org, December 2010, as archived by the Satoshi Nakamoto Institute (retrieved September 2026).
The nine-page whitepaper that started it all: “posted a 9-page paper to a mailing list for cryptographers” · Worth repeating: “Satoshi wrote “block chain,” two words, and only in later posts”
Satoshi Nakamoto, “Bitcoin P2P e-cash paper,” posting to the Cryptography Mailing List (metzdowd.com), October 31, 2008 (retrieved September 2026); “block chain” as two words in Satoshi’s later bitcointalk.org posts, e.g. “Checking the block chain on load,” August 16, 2010, as archived by the Satoshi Nakamoto Institute; neither “blockchain” nor “block chain” appears in the whitepaper.
The nine-page whitepaper that started it all: “an electronic payment system based on cryptographic proof instead of trust” · Who is Satoshi Nakamoto: “The whitepaper cites two of their proposals directly.” · What a bitcoin actually is: “We define an electronic coin as a chain of digital signatures”
Satoshi Nakamoto, “Bitcoin: A Peer-to-Peer Electronic Cash System,” bitcoin.org, 2008. Quotations from Sections 1 and 2; citations to Back and Dai in the paper’s reference list.
Who is Satoshi Nakamoto: “with a newspaper headline about a bank bailout embedded as a timestamp”
Bitcoin block 0, January 3, 2009, containing the text “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks”; software release announced January 9, 2009 on the same mailing list.
Who is Satoshi Nakamoto: “The first transaction, on January 12, went to Hal Finney”
Bitcoin block 170, January 12, 2009, first transaction to Hal Finney; Finney, “Bitcoin and me,” bitcointalk.org, 2013.
Who is Satoshi Nakamoto: “Coins that researchers believe Satoshi mined in 2009 and 2010, roughly a million bitcoin”
Sergio Demian Lerner, “The Well Deserved Fortune of Satoshi Nakamoto,” bitslog.com, April 17, 2013 (about 1 million bitcoin mined by a single early entity and never spent); Lerner’s later “Patoshi” analyses put the figure near 1.1 million, as he confirmed in a Cointelegraph Magazine interview (retrieved September 2026).
Who is Satoshi Nakamoto: “a loose group of cryptographers and programmers calling themselves cypherpunks”
Eric Hughes, “A Cypherpunk’s Manifesto,” 1993; Adam Back, “Hashcash,” 1997 (paper 2002); Wei Dai, “b-money,” 1998; Nick Szabo, “Bit Gold,” 1998 (published 2005); Hal Finney, “RPOW,” 2004.
Who is Satoshi Nakamoto: “the judge ruled that Wright is not Satoshi, did not write the whitepaper”
Crypto Open Patent Alliance v. Wright, High Court of England and Wales, ruling announced from the bench March 14, 2024 (CoinDesk, March 14, 2024); written judgment [2024] EWHC 1198 (Ch), Mellor J, May 20, 2024, judiciary.uk (retrieved September 2026).
Who is Satoshi Nakamoto: “In February 2024, a group of technology companies took him to trial…”
Crypto Open Patent Alliance v. Wright: trial opened February 5, 2024, in the High Court of England and Wales; the judge ruled from the bench on March 14, 2024 (CoinDesk, March 14, 2024).
Who is Satoshi Nakamoto: “It might make sense just to get some in case it catches on”
Satoshi Nakamoto, “Re: Bitcoin v0.1 released,” reply to Dustin D. Trammell on the Cryptography Mailing List (metzdowd.com), January 16, 2009 (retrieved September 2026).
Twenty-one million, and never more: “the world’s gold supply grows by roughly 1.5 to 2% a year”
World Gold Council, “Above-ground stocks,” gold.org (retrieved September 2026): about 222,600 tonnes as of mid-2026; World Gold Council, Gold Demand Trends, Full Year 2025 (2026): mine production of 3,672 tonnes in 2025, about 1.7% of the above-ground stock.
What a satoshi is: “The first version of the software in 2009 introduced eight decimals”
Source code, main.h, 2009: “static const int64 COIN = 100000000;” (earliest version in the bitcoin/bitcoin repository, github.com, retrieved September 2026); the version 0.1.0 release of January 9, 2009 is archived at satoshi.nakamotoinstitute.org/code.
What a satoshi is: “you get 2.1 quadrillion sats, more than 250,000 for every person on Earth”
Arithmetic: 21,000,000 × 100,000,000 = 2.1 × 10^15 satoshis; world population from United Nations World Population Prospects, 2024.
What a satoshi is: “In an April 2009 email to the developer Mike Hearn”
Satoshi Nakamoto, email to Mike Hearn, April 12, 2009, published by Hearn and reported in Vice (Motherboard), August 11, 2017; full text archived at gwern.net (retrieved October 2026).
A bearer instrument and a monetary network: “describes Bitcoin as both a digital bearer instrument and a monetary network” (now on the chapter page, under More from this chapter) · An asset and a network in one: “The newer FedNow service is instant at any hour, but only between banks”
Jack Mallers, founder of Strike, described Bitcoin as “a digital bearer instrument” and as a monetary network on The Peter McCormack Show, September 24, 2021. His weekly program is The Jack Mallers Show, youtube.com/@thejackmallersshow. FedNow: Federal Reserve, FedNow Service, launched July 2023, available 24 hours a day, every day, for participating U.S. banks and credit unions, frbservices.org, retrieved October 2026.
Bitcoin and “crypto”: “One tracking site counted more than 60 million tokens as of September 2026”
CoinMarketCap, coinmarketcap.com, site-wide count of cryptocurrencies tracked, 62.26 million (retrieved September 2026); CoinGecko, by comparison, listed about 21,700 coins the same month.
Bitcoin and “crypto”: “Circle’s USDC are the two largest stablecoins, and the category held roughly $300 billion”
DefiLlama, “Stablecoins,” defillama.com, total stablecoin market cap about $306 billion, of which Tether USDT about $184 billion and Circle USDC about $75 billion (retrieved September 29, 2026).
Worth repeating: “In February 2011 he suggested the name for the smallest unit instead”
bitcointalk.org, ribuck, post in “More divisibility required - move the decimal point,” February 10, 2011, proposing “austrian” or “satoshi” for the smallest unit (retrieved September 2026); the earlier proposal, calling 0.01 bitcoin a “satoshi,” was ribuck’s post of November 15, 2010 in “Official Bitcoin Unicode Character?,” bitcointalk.org topic 369, as dated by the Bitcoin Wiki entry “Satoshi (unit),” en.bitcoin.it, retrieved October 2026.
A fair objection: “In March 2013, a software split briefly orphaned 24 blocks, meaning the…”
Bitcoin Improvement Proposal 50, “March 2013 Chain Fork Post-Mortem,” github.com/bitcoin/bips (24 blocks orphaned; resolved within hours).
The hunt for Satoshi: “Historians of both games and Bitcoin treat the resemblance as coincidence” (now on the chapter page, under More from this chapter)
Cullen Hoback, director, Money Electric: The Bitcoin Mystery, HBO, October 8, 2024, and Peter Todd’s denial the same week, as reported by CoinDesk; Kurt Robson, “Was Bitcoin Discovered in a 1991 Video Game? Inside the Viral Theory Gripping Crypto,” CCN, April 13, 2026 (the buckazoid coin in Space Quest IV, Sierra On-Line, 1991; the game’s designers were Mark Crowe and Scott Murphy; no documented link to Bitcoin). Leah McGrath Goodman, “The Face Behind Bitcoin,” Newsweek, March 6, 2014, and Dorian Nakamoto’s denial the same week (Associated Press); Finding Satoshi, directed by Tucker Tooley and Matthew Miele, released April 22, 2026 (The Block, April 2026).
Tokenized assets, in more detail: “and large asset managers now sell tokenized Treasury funds” (now on the chapter page, under More from this chapter)
rwa.xyz, “Tokenized Treasuries,” app.rwa.xyz, about $14.7 billion across 25 products, including funds from BlackRock (BUIDL), Franklin Templeton (BENJI), WisdomTree, Invesco and JPMorgan (retrieved September 29, 2026).
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