Mining & Consensus

Mining is the competitive process of finding a proof-of-work that makes a block header valid under current difficulty. Consensus rules define what blocks and transactions are valid; miners choose among valid templates.

Why this matters

You may never run an ASIC, but every confirmation UX, reorg assumption, and soft-fork discussion depends on mining incentives and consensus enforcement by full nodes.

Analogy

Difficulty is a treadmill that speeds up or slows down so that bags of work arrive roughly every 10 minutes. If blocks come too fast, the treadmill speeds up; too slow, it eases.

Proof-of-work loop

Difficulty adjustment

Approximately every 2016 blocks, difficulty adjusts based on recent timestamps to keep average block time near 10 minutes.

Soft forks

A soft fork tightens rules in a backward-compatible way. Activation methods (BIP-9 version bits, BIP-8 discussions, Speedy Trial historically) coordinate when new rules lock in. Builders should track whether their libraries and descriptors assume post-fork features (SegWit, Taproot).

Common mistakes

• Believing miners can arbitrarily change supply rules without node acceptance
• Ignoring that empty blocks / fee market dynamics affect confirmation times
• Testing only generatetoaddress on regtest and assuming mainnet propagation behavior matches

Worked mental model

Re-read the diagrams in this lesson once out loud in plain language. If you cannot explain the flow to a friend without jargon, pause and revisit Mastering Bitcoin / Mastering Lightning chapters linked in Resources. Chapter references are intentional, not decorative.

Hands-on habit

Every protocol idea should be paired with one local experiment:

1. Reproduce the happy path on regtest (or Polar for Lightning)
2. Break it on purpose (wrong fee, expired invoice, offline peer)
3. Write down what error you saw and which layer produced it (wallet, node, mempool, peer)

That habit turns reading into builder instinct.

Glossary check

Pick three terms from this lesson and define them in one sentence each without opening notes. Weak definitions mean the lesson is not finished yet.

Resource order

Use Resources in order: narrative book chapter first, then BIP/BOLT for precision, then implementation docs for commands. Jumping straight to RPC flags without the mental model creates brittle knowledge.

Next steps

Move into development: libraries, wallet architecture, descriptors, and Bitcoin Core RPC.