What's a "lead-up strap"?

[Wenny]

Got a breastcollar from the 1940s that has a 1" square ring at the top of the chestpiece. Found two similar rings on breastcollars in a 1942 Hamely catalog. The description in the catalog said "for attaching a lead-up strap". 

Nobody would lead a horse by attaching a strap to their chest, I figure, so it can't be for that. 

I've seen short forks/training forks/martingales attached to breastcollars in similar ways, but I've never heard those called a lead-up strap.

Is it just another name for a fork? Or is a lead-up strap a whole different a piece of cowboy gear?

(click pic to embiggen)

[Tugadude]

For attaching a tie down?

 

[TomE]

I think the lead-up connects a harness breast collar to the breeching; however,  I'm not too familiar with harness.  Mentioned here https://smallfarmersjournal.com/walsh-no-buckle-harness/ and here https://upload.wikimedia.org/wikipedia/commons/8/80/The_harness_makers'_illustrated_manual._A_practical_guide_book_for_manufacturers_and_makers_of_harness%2C_pads%2C_gig_saddles%2C_etc._.._(IA_cu31924000022636).pdf  Perhaps the term also applies to a piece of riding tack?

[Klara]

On 7/1/2023 at 12:04 AM, Wenny said:

The description in the catalog said "for attaching a lead-up strap".

Could it be just a general term for either a martingale or a tie-down? Just any sort of strap that "leads up" to the head?