Bitcoin Forum

so when mining, what makes one share more difficult than another?

for some reason i thought it was the number of 0s but now im not so sure

It's not shares the are more difficult, it's blocks.

Blocks are made more difficult by reducing the target value for the hash.

Miners repeatedly calculate a SHA-256 hash of the block header (modifying a piece of data in the header each time so the resulting hash will have a different value) until the value of the resulting hash is less than a target value.  Increasing the number of leading zeros increases the difficulty by resulting in a lower target value.

As an analogy using base 10 numbers:

000543 is less than 473543, so when choosing a random number between 0 and 999999, it you are more likely (it is easier) to pick a number less than 473543 than to pick one less than 000543.

interesting thanks