Old crochet terminology: "3 under 3 chain" I've recently come across a nice library of antique Irish crochet patterns at a site called APL. I'm having some trouble understanding their language (some of it seems to be different from what we use nowadays).

At this pattern, near the start of the leaf section it says the following:


  [...] a treble in each of 11 trebles, 3 under 3 chain, chain 6


I haven't found any modern resources that would explain what "3 under 3 chain" could mean. This "N  under X chain" pattern repeats later.

What would that be? Is there a modern equivalent of that stitch under modern terminology?

My hypotheses:


It means "yarn under thrice and chain 3", but that would lead to an accumulation of loops across the pattern (it's used multiple times and it never uses such loops)
It means "skip three stitches on the level below the current one", but that has been previously labelled as "miss 3".
It means "three trebles, but with yarn under", but that would ignore the "chain" part of the instruction and not really make any difference.


For context, here's what you get by following the pattern up until that point (with thicker yarn). "A treble in each of 11 trebles" is the last step executed.
After trying to work it our for a while, I gave up and redid the pattern.

With the new configuration, I've come to the conclusion it means "3 treble on the space left between the first 2 stitches (which are a 3-chain), then chain 6". This and the following 2 instructions yield this result, which looks like the top of the leaves pictured in the guide: