Glossary: Fork

Glossary: Fork

Glossary
2 min readUpdated: 17. January 2026 · By Hugo

One-Sentence Definition

A blockchain fork happens when a cryptocurrency’s blockchain splits into two separate paths, creating either a temporary divergence that resolves itself or a permanent split into two different cryptocurrencies.

Why It Matters for Solo Mining

As a solo miner, you need to know which fork you’re mining on because your blocks are only valid on one version of the chain. If a blockchain fork happens and you’re mining on the “wrong” chain that the network doesn’t accept, you’ll waste hashpower earning worthless coins. After major forks, you might also need to update your full node software to stay on the correct chain and keep earning rewards.

How It Works

A blockchain fork occurs when nodes in the network start following different rules about what makes a valid block. Soft forks are backward-compatible upgrades where old nodes can still recognize new blocks as valid, even if they don’t fully understand the new rules. Hard forks are breaking changes where old and new nodes completely disagree—blocks valid under new rules get rejected by old nodes, splitting the chain permanently unless everyone upgrades.

There are also accidental forks that happen naturally when two miners find valid blocks at nearly the same time. The network temporarily follows both chains until one gets longer, then everyone switches to the longest chain and orphans the shorter one. This is normal blockchain behavior and usually resolves within one or two blocks.

Intentional forks happen when developers want to change the protocol—maybe to upgrade security, add features, or change mining algorithms like switching from SHA-256 to something else. Famous hard forks created entirely new coins like Bitcoin Cash (forked from Bitcoin) and Ethereum Classic (which stayed on the old Ethereum chain).

Example

Imagine two kids are building a LEGO tower together following a rulebook. A soft fork is like adding a rule that says “you can now use transparent bricks too”—kids following the old rules don’t mind, the tower stays together. A hard fork is like one kid saying “we’re ONLY using red bricks now” while the other refuses—so they split apart and build two completely separate towers. That’s basically what happened with Bitcoin and Bitcoin Cash in 2017.