Johnny FM probably has a good point, but stitching names get a little confusing because different craftsmen, then and now, have been known to refer to the same stitch by different names. It gets really tough with the French and Germans, because they have a different word for everything. I hear there is a big French and German neighborhood in Europe, but I ain't going there.
One Cordwainer and a bag maker I know referred to back stitching as going all the way down a seam, and then coming back. My master called this tacking ( he'd often spit in disgust when citing it)
Another craftsman referred to back stitching as something I always assumed was called chain stitching.
If you have only one needle, then chain stitching will give you a nice, even stitch even if using a punch and hammer;
That's the BACKSIDE of a seam I just ran. Here's the front side;
To do this, take your needle up through hole one. skip hole two and go back down hole three. Then come up hole two and go back down hole four. If you keep the needle on the same side of the loop on your way up, you can create this chain like effect by staying out in front of the next open hole and coming back around to it on the up stitch.. If you don't want that, then use the flip side where the stitching comes out nice and even.
The picture with the black leather shows the back of the stitching, and the picture with the tan leather shows the chain. Which side you want to show depends on you
The reason I even did this is because I went to Fort William Henry for the umpteenth time and walked by those two dummies on the way in, where one of them is supposed to be a Ranger. He has this screwy looking bag that has always offended me. Out of spite, and some Sambucca in cocoa ( or possibly cocoa in Sambucca) I decided to recreate it.
Yeah, that's paint. Just like the original. Eeeeewwwww. When I got done, I found that the internal pouch placement, lightweight and easy carry worked well on the range. Now I can't decide whether or not to have the nerve to show up at a trail walk with it. Probably need to Psych up with Last of The Mohicans.