<p>If a block is part of the main chain, that means that the tip of the blockchain is a descendant of that block. </p>

<p>If a block is not part of the main chain, that means there is a longer chain of blocks that does not include this one. These are called orphaned blocks or invalid chains.</p>

<p>If a block is in the main chain, its parent is automatically in the main chain too. </p>

<p><img src="https://i.sstatic.net/7MmR4.png" alt="blockchain"></p>

<p>In the above figure, the black boxes are the main chain. The grey blocks are invalid chains. The green box is the genesis block.</p>

CC BY-SA 3.0
2014-10-24T01:46:17.560Z
2014-10-24T01:46:17.560Z
Nick ODell
<p>What does it mean that for bitcoin block to be on the Main Chain? What other chains are there? Is this as opposed to testnet?</p>

<p>This is regarding the main_chain value in the blockchain.info api here:  <a href="https://blockchain.info/api/blockchain_api" rel="nofollow">https://blockchain.info/api/blockchain_api</a></p>

<blockchain><blockchain.info><best-chain>
What does the main_chain value returned by blockchain.info mean?
Derrick
# What does the main_chain value returned by blockchain.info mean?

(Asked by: username_0 on 2014-10-24)

What does it mean that for bitcoin block to be on the Main Chain? What other chains are there? Is this as opposed to testnet?

This is regarding the main\_chain value in the blockchain.info api here: <https://blockchain.info/api/blockchain_api>

**Tags:** blockchain, blockchain.info, best-chain


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## 1 answers

### Answer by username_1 on 2014-10-24. Score: 3 | Accepted answer

If a block is part of the main chain, that means that the tip of the blockchain is a descendant of that block.

If a block is not part of the main chain, that means there is a longer chain of blocks that does not include this one. These are called orphaned blocks or invalid chains.

If a block is in the main chain, its parent is automatically in the main chain too.

![blockchain](https://i.sstatic.net/7MmR4.png)

In the above figure, the black boxes are the main chain. The grey blocks are invalid chains. The green box is the genesis block.


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