Sail?

[WanderingStar]

In the current Cruising World there is a picture by Webb Chiles of an apparently light running sail with a corner at the top leeward edge. A sheet (brace?) attaches there, and another line also. I've never seen one, any one know what it's called? The sail has round edges, but four sides.

[Faster]

Sounds similar to what schooners run as a 'Fishermans Staysail.

I've seen pics of genoas like that on some of the old J Class yachts too. Don't recall the name of it.