Quote from: IggySe7ven on Today at 07:50:45 PM

Guys, maybe I am not understanding something , I am learning this course on "IvantheTech" its called Bitcoin101

and there they talk like Miners in different parts of the world can simultaneously mine a block and send it to nodes and etc but then one of the 2 miners that send different block will eventually get rejected, that when the next block is mined after the block with my transaction on it that if there is 2 groups of nodes with different versions of same block that whichever group adds another block next will get accepted because blockchain accepts the longest chain and so the other version will eventually become "stale blocks and be moved to mempool".

I dont understand , how do we have a choice how many confirmations we can wait? I thought If I send bitcoin to another adress, the other adress will not see it on the chain until 6 confirmations. Do we actually have a choise how many confirmations we recieve until we can send that transaction to another another adress without it being denied?

With 6 confirmations you ensure that miners will not mine simultaneously the same blocks. You do that with fewer blocks too, but this is not the reason why 6 confirmations are needed. As you can see from @Royse777 post, the power of unknown (and known) cpu pools are huge. Let's say that there is a small possibility for a pool to mine 2 blocks at the same minute and your transaction has 1 confirmation. Yes, they could remove your transaction from the blockchain. With 6, though, it's impossible. It requires more than half of that CPU power. Satoshi wrote it on his whitepaper [11) Calculations]

Quote from: IggySe7ven on Today at 07:50:45 PM

I dont understand , how do we have a choice how many confirmations we can wait? I thought If I send bitcoin to another adress, the other adress will not see it on the chain until 6 confirmations. Do we actually have a choise how many confirmations we recieve until we can send that transaction to another another adress without it being denied?

When someone sends you bitcoins, even if the transaction is not confirmed, you can spend them. The problem is that, in order for your transaction to be confirmed, the first transaction must be confirmed first.

No you don't have to wait 6 confirmations to spend your funds.