Shallow Hole On Many Ancients

If its what I am thinking of,its mostly on provincials
and it is made in the minting process,to hold the flan.

The holes are called "centration marks", or "centration dimples", because one of the main theories about what they're for is they come from the coin blank being screwed into some kind of lathe-like device, to smooth the surface and round the edge prior to striking. There are always two holes, one reverse and one obverse, and they normally (but not always) line up pretty evenly. They're only ever found on medium-to-large sized bronze coins, and they occur far more commonly in some series than in others; Ptolemaic Egypt and Roman Bulgaria appear to be two coin series, widely separated in time and space, where the marks can be found on almost every bronze coin.

But in truth, nobody knows for sure what mechanism put the there, or why. Another leading theory is that the blanks were heating prior to striking by being held with tongs in a furnace until the blank just started to soften and melt; the dimples would come from the tongs.

Because they were placed on the coin prior to striking, they're considered a normal part of the coin, and not an error or damage - the best modern equivalent phenomenon would be "ghosting". As such, it doesn't normally affect the value one way or another, unless it's a particularly spectacular example.

Saps' answer is pretty spot on though they actually can be found on quite small bronzes as well (at the 17mm mark or so) so it seems to relate to the minting process that happened to occur at a particular place and time

There is a current informative thread on Forvm at the momment on this

http://www.forumancientcoins.com/bo...opic=51009.0