I have, for some reason, been under the impression that traditional coch-y-bondhu (or bonddu) hackle was a dark red with black center and tips. However, on p. 212 of Robert Smith's book he shows a photograph of coch-y-bonddu hen feathers that are primarily black with a light gold list and tips. Live and learn as they say.
Some of the same morons who throw their trash around in National parks also vote. That alone would explain the state of American politics. ~ John Gierach, "Still Life with Brook Trout"
It's my understanding that it could be any of several variations, depending on where you're from and where you live. As a hackle description, it started out meaning "the right hackle for the coch-y-bonddu beetle imitation" and usually was synonymous with "furnace". The meaning has changed over the years so that more people today use it to refer to black-red-black or red-black-red, depending on where you're from.