<p>I think you mean a fork. Blockchain has forked if a block has got two or more children blocks. In bitcoin there is a longest-chain rule, that means that only the longest chain is valide.</p>
<p>At the same time, there is a possibility that an attacker can catch up from a given deficit of k blocks. But the probability that this will happen decreases exponentially with k.</p>
<p>In the white paper, Satoshi Nakamoto got some calculations. If an attacker has 10% of the network power, he can catch up to 6 blocks with a probability of less than 0.1%. That's why I think 6 blocks is something canonical. But some people and services wait less than 6 blocks. For example, some mixers may wait even 1 block.</p>

CC BY-SA 4.0
2022-07-16T23:00:40.463Z
2022-07-16T23:00:40.463Z
Evgenii_BO
<p>I believe you are referring to the &quot;longest chain&quot; where two nonce are found and the respective blocks are broadcasted simultaneously. The following is an excerpt from the bitcoin whitepaper describing this scenario.</p>
<p>Section 5: Network: <a href="https://bitcoin.org/bitcoin.pdf" rel="nofollow noreferrer">Bitcoin Whitepaper</a></p>
<p>&quot;Nodes always consider the longest chain to be the correct one and will keep working on
extending it. If two nodes broadcast different versions of the next block simultaneously, some
nodes may receive one or the other first. In that case, they work on the first one they received,
but save the other branch in case it becomes longer. The tie will be broken when the next proofof-work is found and one branch becomes longer; the nodes that were working on the other
branch will then switch to the longer one&quot;</p>

CC BY-SA 4.0
2022-07-16T02:02:00.967Z
2022-07-16T02:02:00.967Z
Moussa Al-Basheer
<p>I'm trying to find more information on this topic but I can't remember what this is called in order to look up more information on it.</p>
<p>Is there an easy way to see the &quot;trusted&quot; amount of confirmations? I've noticed many people consider 3 confirmations to be good, however for larger transactions 6 is better. I've heard that bitcoin has had separate chains goings for 3, maybe 4 blocks.</p>

CC BY-SA 4.0
2022-07-16T13:50:03.037Z
Are you looking for one of the tags [tag:blockchain-fork], [tag:best-chain], or [tag:chain-reorganization]?
Murch
<blockchain><terminology>
Whats it called when two blocks are solved at the same time and create their own chain?
Trevor
# Whats it called when two blocks are solved at the same time and create their own chain?

(Asked by: username_0 on 2022-07-16)

I'm trying to find more information on this topic but I can't remember what this is called in order to look up more information on it.

Is there an easy way to see the "trusted" amount of confirmations? I've noticed many people consider 3 confirmations to be good, however for larger transactions 6 is better. I've heard that bitcoin has had separate chains goings for 3, maybe 4 blocks.

**Tags:** blockchain, terminology

> **Comments:**
> **username_1**: Are you looking for one of the tags [tag:blockchain-fork], [tag:best-chain], or [tag:chain-reorganization]?  

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## 2 answers

### Answer by username_2 on 2022-07-16. Score: 1

I think you mean a fork. Blockchain has forked if a block has got two or more children blocks. In bitcoin there is a longest-chain rule, that means that only the longest chain is valide.

At the same time, there is a possibility that an attacker can catch up from a given deficit of k blocks. But the probability that this will happen decreases exponentially with k.

In the white paper, Satoshi Nakamoto got some calculations. If an attacker has 10% of the network power, he can catch up to 6 blocks with a probability of less than 0.1%. That's why I think 6 blocks is something canonical. But some people and services wait less than 6 blocks. For example, some mixers may wait even 1 block.


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### Answer by username_3 on 2022-07-16. Score: 0

I believe you are referring to the "longest chain" where two nonce are found and the respective blocks are broadcasted simultaneously. The following is an excerpt from the bitcoin whitepaper describing this scenario.

Section 5: Network: [Bitcoin Whitepaper](https://bitcoin.org/bitcoin.pdf)

"Nodes always consider the longest chain to be the correct one and will keep working on
extending it. If two nodes broadcast different versions of the next block simultaneously, some
nodes may receive one or the other first. In that case, they work on the first one they received,
but save the other branch in case it becomes longer. The tie will be broken when the next proofof-work is found and one branch becomes longer; the nodes that were working on the other
branch will then switch to the longer one"


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