Block Number Matters With Cryptocurrency Hard Forks: Understanding Snapshot Blocks and Block Height

The block number (AKA block height) tends to matter more than the date with crypto forks. In many cases a snapshot for a fork will happen at a block height, and the date is secondary.

One can only approximate the date a certain block height will happen on. Thus for many forks and airdrops with a snapshot, the date is an approximation of a specific block height.

Back in 2017, many people were talking about dates with Bitcoin Gold, throwing out dates like Oct. 25th. However, ultimately it was a specific block (as one logically might have suspected) that mattered. In fact, those who waited until the 25th missed the fork (it happened on the 23rd).

The same confusion tends to surround other forks and airdrops in general. There are many examples of this being the case, but in each case the logic is the same. The block height, not the date, is often what matters… of course, sometimes the date does matter. In those cases, you should pay attention to what format the date is in (it’ll usually be in Unix timestamp or Universal Time Coordinated).

When date matters: In some cases developers plan forks for a date and time (usually offering a very specific and universal time, for example a time in Unix timestamp or Universal Time Coordinated), and then fork at whatever the block height is at that date and time (this was the case with the Zclassic fork for example). In these cases, the date matters and the block height at that date is secondary.

On Airdrop Snapshot Block Heights: In general what is true for traditional forks in terms of snapshots and block height is true for airdrops in which a snapshot is taken at a “airdrop snapshot block height.” This is also true for most claims, giveaways, etc.

What is a snapshot? A snapshot is  copy of the blockchain made at a specific block height or time. With a cryptocurrency fork, you must be in that cryptocurrency, generally in a wallet where you control your private keys, before the snapshot block (your transaction must be added to the blockchain, it can’t just be started). Then, sometime after the snapshot, the new coin will be able to be accessed using the keys of the wallet in which the cryptocurrency was held during the snapshot (one must configure an existing wallet or download the official wallet of the new coin and then access it with the existing keys). In other words, step 1 is being in BEFORE the block in mind, step 2 is waiting for the official word on how to claim the coins (with an airdrop, you’ll “add the token” with a traditional fork you’ll download the new wallet and use your keys to configure that). Something to keep in mind is that you can wait to claim your coins, as long as you have access to your wallet and had cryptocurrency in that wallet at the time of the snapshot, you can claim your coins from a given fork once the mainnet (main network) goes live.

How to know what block we are at: One simple way to keep track of what block we are at is with a block explorer. With Bitcoin a block is mined roughly every 10 minutes, but this fluctuates (which is why one can only estimate the exact time a block will occur). Other coins mine blocks at different speeds.

The Logic Behind Block Numbers Mattering

And the above makes sense if you think about it. If a blockchain is going to split, it must split at a block (and many blocks happen each day). Likewise, and more specifically, if the developers are going to take a snapshot of the ledger to get existing balances, they have to take a snapshot at a block height.

A blockchain is like a clock in that it records time sequentially as blocks are mined.

On-the-wall calendar dates can be somewhat meaningless with forks, as even a specific date and time on a calendar/clock is arguably still better described in terms of block height on a blockchain.

Thus, although block height isn’t the most important factor for every fork or airdrop, one should generally assume that holding during a specific block is what matters with cryptocurrency forks and airdrops.

One can give a rough date of when a Bitcoin block will occur by treating every Bitcoin block as 10 minutes for example (it differs for other coins), but the time it takes to mine a block (which involves committing it to the blockchain) is variable. This means no one can perfectly predict the date a block will occur on (although estimates get more precise the closer we get to the block).

And So It Was and So It Has Been and So it Will Be

Back in 2017, for a month straight we heard “Bitcoin Gold is October 25th, the 24th, the 26th, etc”… but it wasn’t any of that, it happened earlier than expected on the 23rd at block 491,407. It had nothing to do with the magic date 23… it was all about block 491,407.

With the Segwit2x fork, those who held Bitcoin at block 494,784 were supposed to get 1 Segwit2x Bitcoin for every Bitcoin they held (that fork didn’t end up happening, but if it did it would have worked like that).

It generally worked like this for Bitcoin Cash too!

The same has been true for the many forks that came after these as well.

More Considerations

The above isn’t the only thing to think about, it is just the lynchpin.

One must also consider where they hold a given coin. If one holds on an exchange or via a broker like Coinbase, they may have their own rules (so the snapshot block height of a fork won’t always be exactly the same as a the snapshot block height used by an exchange).

In cases you may have to have your coins on an exchange 24 hours before or keep them sometime after (as they may shut things down to take a snapshot). In other cases an exchange might not support a fork at all.

Still, while there is more to consider, remembering that the BLOCK NUMBER MATTERS with crypto forks is going to save everyone a headache down the road. So, remember that.

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