$1936

so you know how with a standard kumihimo you leave 3 strands down/1 strand up and that's how you know where you left off?

well I'm looking into this https://craftdesignonline.com/kumihimo/hollow-braid/

and I cannot figure out, for the life of me, how I'd stop and come back to it.

What you could do is put a marker on the last thread you moved. And if I’m right, for this braid you always have a group of one and a group of 3 if you haven’t done a whole round yet. So the next thread is always the middle one of the group of 3. You only need to remember if you need to go right or left.

I think you always do full rounds and you could start anywhere in the round. It's just important to alternate the clockwise and counterclockwise rounds.

Here is a tutorial https://prumihimo.com/resources/braiding-patterns/hollow-braid/

I have not tried it myself so I cannot promise that I understood it properly

maybe this is too much for me right now. I start and stop A L O T and I'm not sure that kind of braid is gonna turn out right with me