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The Bitcoin School
For people who want to understand Bitcoin. Not flip it.
Plain language. Sourced chapters. Live on-chain data from a real node. Huge glossary, Rabbit Holes, and one opinionated Journey from "what is money?" to running a full node. No altcoins, no affiliate links, and no signup needed to read any of it.
From the glossary
After several confirmations, reversing a transaction by reorg becomes highly improbable, ensuring practical finality.
Read full entryNew on the site.
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Rabbit Hole · 16 min
The Time Warp: How Lying About the Time Could Break Bitcoin's Difficulty
A seam in Bitcoin's 2009 code would let a miner with most of the hash rate drive difficulty to its minimum within weeks, in under six with all of it. It has been used on other coins and planted once on testnet, never used on Bitcoin, and the fix is written and waiting for a soft fork.
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Rabbit Hole · 14 min
Quindecillions: Why Nobody Can Stumble on Your Bitcoin
After a vanity address search, readers ask whether the address already had coins in it and how many wallets the search found on the way. Every Bitcoin address is a drawer. There are about 1.5 x 10^48 of them, 57 million hold coins, and no search on record has landed on a funded one by chance. The same arithmetic is why nobody has to register a key before using it.
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Rabbit Hole · 15 min
Which Coins Does Your Wallet Spend?
Your wallet does not have a balance. It has a bag of coins, and every payment starts by choosing which to spend. What that choice costs today, what it costs later, what it tells a chain analyst, and how the reference wallet decides, with four algorithms and one score.
No bullshit.
No price predictions. No affiliate-bait. No fear marketing. Every chapter cites its sources, and the live on-chain numbers come straight from a full Bitcoin node.
Have fun.
Interactive, opinionated, well-crafted. Rabbit-hole vibes. Built by Bitcoiners for people who want to actually understand.
Down the rabbit hole.
All rabbit holesCustody and Privacy
How do I hold it safely and privately?
- Mt. Gox to FTX: The Custody Graveyard
- Privacy on Bitcoin: What Works and What Doesn't
- Use It Once: Why Reusing a Bitcoin Address Is Dangerous
Hard Questions
The strongest objections, including where the critics are right.
- Quantum and Bitcoin
- Bitcoin and Energy
- Rat Poison, Tulips and a Pet Rock: Everything Bitcoin's Been Called (so far)
Corrected in public.
All corrections-
It now says a transaction counts when any of its inputs is Taproot, the definition mainnet.observer uses, links that chart next to the numbers, and gives the January 2024 figure as the whole month (63.1 percent; 5.2 percent over the 30 days ending 17 September 2026), recomputed from mainnet.observer's public CSVs.
What was wrong -
Dividing two weeks by 2,015 gives 600.3 seconds, while blocks at constant hash rate average about 600.6 (Wuille). Bitcoin Inquisition has enforced BIP-54 on signet since February 2026. Two hours was a precaution after testnet4 exposed pool software that stamped blocks from its own clock, and under a sustained attack it costs about three seconds a block (599.9997 against 596.7211 seconds in Wuille's simulation). Testnet3 carries a time warp Greg Maxwell planted on purpose in July 2012; the 2024 storms were the minimum-difficulty bug. The discovery is now dated: ArtForz, BitcoinTalk, 12 September 2011.
What was wrong -
29.0 covers the time warp rule; the negative-window rule reached Bitcoin Core's templates in 32.1 (PR #35949, October 2026). Two hours was a precaution, at a cost of about three seconds a block under a sustained attack.
What was wrong