Bitcoin Forum

I've been looking at blockchain.info for a while and I already saw it happening twice that a block was confirmed with only a single transaction inside. The first time I saw this, I found it very odd that someone was so lucky to find a block so soon that there weren't any transactions done in the meantime. But now I saw it happening again and I clicked on the block for some more information.

It was block #294422 and it still seems odd to me. In fact there were no transactions done in the block but only 25 BTC credited to the miner (I guess) which has address 1K7znxRfkS8R1hcmyMvHDum1hAQreS4VQ4. Looking into this address, the blockchain tells me that this address might not be trustworthy as it has double spends. When I look into the transactions I see that this address quite often receives 25 BTC, apparently for finding new blocks.

Is this a coincidence? Did someone create a client that can actually take part and at the same time not take part to the network by finding blocks without any transactions and thus creating coins for themselves?!

Could someone explain this? Could this be a bug or exploit?

Edit: something else; block 294421 was found 47 minutes ago, 294422 was found 22 minutes ago, 294423 found 27 minutes ago and 294424 26 minutes ago. Why is this 1 transaction block 'younger' than the 2 blocks that have a higher ID?

Happens all the time.  No big deal.  There is nothing in the protocol that requires miners to include transactions in their blocks.  Of course the miner misses out on all the transaction fees if they do that, leaving all those fees from miners that mine the next block.


Nope.  Just a normal part of the design of bitcoin.


Timestamps are not exact on bitcoin blocks.  They are allowed to drift by up to 2 hours in either direction.

So there is no specific advantage this miner is exploiting to create 25 BTC each time it finds a block? It seems so strange to me that this single address so often finds a block (what are the odds) but always without transactions.

Anyone can mine blocks. It might be someone that owns a huge farm of hashpower.
You don't have to include transactions in blocks, and so they don't.
They are not exploiting anything.

Nope.  No specific advantage creates 25 BTC. Every block right now creates 25 brand new bitcoins.  It doesn't matter if the block has 1 transaction or 4000 transactions (or any other amount of transactions).  It still creates 25 brand new bitcoins as a block subsidy.  In addition, the block reward includes all the transaction fees of all the transactions that are included in the block.  If a miner chooses not to include transactions, then they are choosing not to earn as much money as they could.  Financially this is generally a bad decision.  Other miners (and mining pools) that include transactions in their blocks will earn more money and therefore be able to operate with higher costs or lower income than a miner that doesn't include transactions.


It could be an address for a mining pool, or it could be an individual with a huge amount of hashing power.


Difficult to know.  That depends on how much hash power they have access to.  It could be quite likely.


As I said, that's a very poor financial decision on their part, and may lead to them eventually losing money and shutting down their equipment.

OB-Pedantic: the timestamps are bounded by needing to be greater than the median of the last 11 blocks in their chain and less than two hours in the future from the perspective of each validating node.

Ok thanks for clearing this up!

It is not true that a block without transactions has no advantage. If you broadcast a block with 0 transactions, the size is very small, so it gets broadcast a second or so faster. This leads to less orphans. If the percentage rate of orphaned blocks goes down more than the transaction fees bring, than it would be wise to not include transactions. (this is from a pure +EV perspective).

Economically speaking, it is NOT wise for ANY miner to include 0 fee transactions.

Im lost on this one....how ISNT it economically viable if you can get more blocks solved and submitted?  How could I even solo mine to do this? You know, not include trx fee blocks - are you guys saying that when one does this they will get fewer blocks than they would have with the trx fees.  It makes sense to ignore the trx fees if it means that I get more blocks in.

You dont get More blocks. This is 100% depending on your hashrate. But less off your Blocks get orphaned because they are smaller and faster transmitted.

Many people tried to calculate if including txs that ha e a fee is actually positive EV,and most calculations agree that it is, but txfeefree transactions can never be +EV inmy opinion!

there been not so many blocks without transaction fees

however check this out http://organofcorti.blogspot.de/2014/03/181-who-owns-1htm4tysxf5yzklpco6mtuunfs.html (http://organofcorti.blogspot.de/2014/03/181-who-owns-1htm4tysxf5yzklpco6mtuunfs.html)

as the address OP mentioned is is in this blog