When is a split not a split?

[Doghouse Reilly]

why is a split not a split if the head pin is standing?

For example the 2-4-10 is a split but the 1-2-4-10 is not a split. Is it just because they say if the head pin is standing there is no split just a washout or is there different reason?

[jimlc2001]

Any leave that includes the head pin is not a split. That's it.

[J Anderson]

I've never understood why its not called a split, but it isn't.

[vgw]

if the headpin is up, it's not considered a split. Don't forget the baby splits too... like a 4-5 or 7-8....