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Mainchain (Layer 1)
The mainchain is the base Bitcoin ledger.
It stores the shared history of ownership.
Education only. No financial advice.
The mainchain is slow on purpose.
It focuses on global verification and settlement.
Three key ideas
These ideas explain why Layer 1 looks different from payment apps.
It has different goals.
Everyone can verify
A node can check the full history.
This keeps the rules consistent across the network.
Security over speed
The chain moves in discrete blocks.
That creates a natural pace for settlement.
Limited block space
Each block has limited capacity.
This creates a market for inclusion.
What is the mainchain?
The mainchain is the base layer ledger.
It is shared by many independent nodes.
A ledger is a record of who owns what.
Bitcoin uses a public ledger with strict rules.
A node is software that validates the ledger.
It checks blocks and rejects invalid history.
The mainchain is also called Layer 1.
It is the foundation for other layers.
Higher layers can improve speed or privacy.
They still rely on Layer 1 for settlement.
Transactions and blocks
A transaction moves value by changing ownership.
A block groups transactions into a time-ordered record.
What a transaction is
A transaction is a signed message.
It authorizes new ownership of specific coins.
What a block is
A block is a bundle of valid transactions.
It also links to the previous block by a hash.
What a hash is
A hash is a short fingerprint of data.
Small changes produce very different hashes.
Mining and Proof of Work
Mining is the process of building blocks.
Proof of Work is the cost that protects the chain.
Mining is a competition to find a valid block header.
Miners try many random values called nonces.
A nonce is a number used once in the search.
It changes the hash output.
Proof of Work is a puzzle with adjustable difficulty.
The puzzle is solved by trial and error.
The solution is easy to verify.
This lets nodes check blocks quickly.
Security through energy
Proof of Work uses real resources.
This makes attacks expensive to sustain.
Attacks need ongoing work
Rewriting history needs more work than honest miners.
The attacker must keep paying the cost.
More blocks add weight
Each new block builds on the last.
Older blocks become harder to replace.
Nodes check everything
Nodes verify signatures and rules.
Work alone cannot bypass valid rules.
Settlement and finality
Settlement is recording a result on Layer 1.
Finality is confidence that the result will not change.
Settlement means the transaction is in the mainchain.
It becomes part of the shared history.
Finality is not instant.
It increases as more blocks confirm the transaction.
A confirmation is a block added after your transaction.
More confirmations mean more accumulated Proof of Work.
Finality is a spectrum, not a single moment.
It depends on your risk tolerance.
Why block space is limited
Block space is the capacity inside a block.
It is limited to keep nodes affordable to run.
History must fit on devices
Every full node stores the blockchain data.
If it grows too fast, fewer people can verify.
Blocks must travel globally
Nodes share blocks over networks.
Big blocks take longer to reach everyone.
Rules must be checked fast
Nodes verify signatures and scripts.
Larger blocks require more computation.
Why fees exist
Fees are payments to miners for including transactions.
They coordinate scarce block space.
When demand is high, not all transactions fit.
Fees help miners choose which transactions to include.
Fees can change over time.
They reflect competition for block space.
Fees also reduce spam.
Spam is low-value data sent to overload the network.
The goal is stable verification for everyone.
Low-cost nodes help decentralization.
How the layers fit together
Layer 1 anchors the system.
Layer 2 and Layer 3 can reduce on-chain usage.
Layer 1 provides settlement and shared rules.
Higher layers build useful payment experiences.
Users choose if that trade-off is acceptable.
It can settle disputes on-chain.
This keeps decentralization stronger.
Common misunderstandings
These points are frequent sources of confusion.
They are simplified but honest.
-
Mining does not create rules.
Nodes enforce rules, and miners must follow them. -
A block is not a single payment.
It is a batch of many transactions. -
Finality is not instant.
It grows with confirmations and total Proof of Work.
FAQ
These answers keep the focus on learning.
They avoid promises and price talk.
Does Proof of Work mean the chain is unchangeable?
Proof of Work makes changes costly.
Deep history becomes very hard to rewrite in practice.
Why can a transaction be replaced before it confirms?
Before confirmation, a transaction is in the mempool.
The mempool is a waiting area, not final settlement.
Why not increase block size forever?
Larger blocks increase costs for nodes.
Higher costs can reduce the number of verifiers.
Ready to learn Lightning?
Lightning builds on Layer 1.
It is designed for fast payments with clear constraints.