So I thought I'd go into some of the other candidates suggested as the "odd one out". PeteW came up with lots to work with. Viz:
Extreme top-left, appears to be your only oriental-style chisel
Which is quite true. The Japanese set I was curious about and decided to try was kicked into touch many years ago now; the hollows in the backs just didn't suit me and that was that. Now contain your surprise, but I came to own this chisel because I was also... curious. Yeah I know, you didn't see that coming at all.
It's a Chinese stylee broad chisel with an HSS blade soldered to the body (Or maybe braized? Like I know the difference...) Think I may have got it from Rutlands in a moment of weakness. Or maybe Workshop Heaven? Neither of them have them any more though, which I'm inclined to think may be our loss.
Dim memory suggests it came to me under the auspices of the Mujingfang label, and if you've ever seen El Presidente's photos of their state of the art plane factory, you can certainly see chisels along the same theme in use to make those surprisingly excellent tools. You can probably also hazard a guess at the equally state of the art production that makes the chisels...
Okay, the back isn't pretty, it's true, but wait to you see the other side:
It's, um, "honest". No artifice here. No surplus polishing or grinding. It's some bits of metal all whacked together and clobbered until they made a chisel. I rather like it; kind of a connection with Western chisels of yore and they're similar habit of taking the minimum of cutting steel and making it go a long way.
And seriously, don't let the looks fool you - it takes a wicked edge and I have no hesitation in belting the snot out of it when necessary. Does it care? Does it wilt in the face of such abuse? It does not. Yeah, I've chipped the edge and all sorts, but it's HSS, so Hah! Take it to the grinder with impunity and have at it; in no time you can have that wicked edge right back.
So far I've stamped on my curiosity sufficiently to resist purchasing any more Chinese style chisels, but it's not easy 'cos I've heard good things about these...