What is this?
 

I was shopping for basses, and came across this black strip of wood on a couple basses from totally different manufacturers (different continents, different decades...) and was wondering what it is. I am imagining that it might be a way to hide a neck joint repair, as both basses had a split as seen in the blurry photo.

Any ideas?

To save money on wood, manufacturers often use neck blocks that aren't quite deep enough to get a full heel out of. A lot of repaired necks will have a similar shim, but hopefully not that long. That to me looks like a neck in need of repair.

Edit- Realized you were talking about the ebony strips. They are just decorative and hide the end grain of the ribs. Many makers use them.

Joey, same thing happened to me. I got sucked in by the separating neck and forgot to read the question.

That's a built-up heel and isn't necessarily coming apart. I see them like that often - the two pieces of wood have slightly differing shrinkage rates and have cracked the finish but its not always a complete separation. Photo's a little blurry, eh?

The ebony filler strips are probably original. I'm partial to the look, personally. ;)

My carved Romanian flatback (Roma, I think) has a strip just like that. In fact, that could be a picture of my bass.