Derek:
I think you hit the nail on the head.
Pat:
The Japanese chisel is simply a better, and much more sophisticated design, with more antique but superior metallurgy, and typically better executed . One needs to use them before this becomes clear.
And yes, the hooped chisels are hard on the hands for lots of pushing. Some people remove the hoops entirely if they do mainly paring. But Japanese paring chisels are an elegant and very effective solution to this shortcoming, IMO.
The steel used varies from maker to maker and chisel style to chisel style. The consumer-grade ones are made from SK5, which is a standard run-of-the-mill (kinda-) high-carbon steel very similar to O1 or 02, but a little purer (no chrome). The better ones are made from even purer types of high-carbon steel. Better steels, combined with hand-forging (improves the grain structure and makes the cutting edge more durable) makes their cutting and sharpening performance unsurpassed by anything being produced nowadays. Sharpness and durability, however, come at a price, which is harder steel. A chisel made from one piece of steel and hardened to the necessary degree would break. Guaranteed. The iron/low-carbon steel body of the traditional Japanese chisel keeps the hardened steel cutting edge from breaking. This is part of the excellent design I touched on above. Anyway, it is the hardness of the cutting edge, its durability, and the ease of sharpening that differentiate Japanese chisels from Western chisels.
It wasn't always that way. American and English blades from the 1800's were hand-forged from high-carbon steel, and some of them cut and sharpened very very well indeed, in my experience. But they aren't as hard as Japanese chisels because of the breakage risk. And you can't buy those blades new anymore. Chinese peasants working in factories are not experienced blacksmiths, and cannot produce products of similar quality, or even appearance, using high-carbon steel.
I have not used the powdered metal chisels, but I own and use knives made from similar metals. They are very durable, and don't rust as easily, but they don't get as sharp as, and are more difficult to sharpen than White Paper or Blue Paper steels. Powdered metals have lots of advantages, as I know from my day-job, but the biggest are consistency (QC) , ease of mass-production, and the ability to create relatively complex shapes (like gears) in pressure molds to high tolerances and with very little machining. Chisels are not a complex shape. Consistency (QC) is nice since sintered metals make possible and economical some amazing alloys difficult to produce in a pot. But do the alloys make a better chisel? Ease of manufacture is great if it translates to lower prices. But performance is what matters the most, and only you can decide what it is for you. I suggest you buy good examples of drop-forged chisels, cast chisels, powdered metal chisels, and hand-forged high-carbon chisels and try them out.
I own 30 or so chisels by Kiyotada (Shimamura), and another 15 or so by Ichihiro (Hidari-no-ichihiro = Yamazaki). I met these blacksmiths, and we talked about chisels and steel. They custom-made my chisels for me 30+ years ago. I learned how to use them and maintain them from professionals. I used them professionally for a number of years to feed wife and babies. A famous metallurgist named Iwasaki wrote that Kiyotada's chisels were the best ever made in Japan. These are standard by which I judge all chisels.
Before Kiyotada and Ichihiro, I owned and used a number of famous brand chisels, including products from the Miki companies like Koyamaichi, Ouchi, etc.. Too soft for my taste, so I sold them all after getting my hands on Kiyotada and Ichihiro products. Later, I found myself back in Japan without chisels and bought a set of Kiyohisa oirenomi. They were White Paper #1, and quite expensive, so I had high expectations. I was told they were the best available since Kiyotada and Ichihiro had both gone to the big woodpile in the sky. Most of the Kiyohisa chisels were disgustingly soft. Others chipped like Tiger Woods. I went on the hunt for blacksmiths that produced professional-grade chisels at a reasonable price, and found that there are still a few old-boys making chisels for people that use chisels. I sold the Kiyohisa set for a profit.
Anyway, the last 2 paragraphs have nothing to do with your question, Pat. Suffice it to say that, in general, Japanese chisels are worth owning and using. There is a bit of a learning curve, but it is worth it.
Stan