WHAT A GREAT POST!!! Seriously it is nice to hear from someone who knows his stuff. I concur with everything you said about BD1. We found the same things when we tested it. When carpenter first created it, their goal was to emulate a slightly better 440c steel. It is truly astounding how much it changes when it goes throught he nitrogen treatment. Again carpenter doesn't even get it. I can say that to date after shipping for almost three years, we have still not had a single rust or chipping return. With regards to knives bending, I have a funny story for you. My first day a shun, I looked at my inventory, and saw that I had exactly 39 piees for the entire country. three of each shape. that is also the day I met Ken Onion, who later became my dear friend. However at the time, Ken felt it was necessary to take one of my 10" cooks knives and bend it right in front of me. Instead of trying to understand what he was trying to show me, I was furious that he had just reduced my inventory by one third on that item. I later realized that what he was showing me, was that the only steel heat treated in the layered knives was the cutting core. The outer layers were still soft. In the case of Dragon and German knives, this isn't the case because you have one piece construction. The entire blade is heat treated so the knives don't bend.
For those of you who are new to this, if steel is not heat treated, it is bendable like a paper clip. Heat treating is what gives it its strength and rigidity. The recipie of the steel and how it is manufactured, determines how hard you can make it. This is the HRC rating we are always refering to. If you heat treat the steel past the number it is rated to, it becomes brittle and useless. BD1N is rated at 63HRC. Most german steels are rated between 53-58HRC. Up untill recently, only chromium could make steel stainless, but it weakened it terribly, which is why it has a low HRC rating. The nitrogen changes things so that you can heat treat it higher, and have it still be tough. Lobster is correct when he points out that many Japanese blades can end up bent. In fact if you go to one of the top tow gourmet stores, you will notice that they will never take one of the knives off the bar to show you. they keep fresh ones in the drawer. We found out that they were using such powerful magnets, that when they slapped the knife on the bar, it would end up bent. Layered steel knives can also end up bent during the grinding process, or during sharpening, if the sharpener is heavy handed. Let me state clearly, that this does not make layered steel knives bad. I still feel they out perform any european knife. Just don't hammer a nail with them, and you should be fine.
With regards to your question. you need to be more specific with which shun handle you are asking about. With regards to shun classic, it is a pin tang. for novices, that means that they take a thin piece of metal and screw it into the bolster then the end cap is screwed onto the other end to keep it together. It is very strong. We used to Joke that it would take a blow torch to break into a shun handle. With regards to dragon, the bolster and end cap are cast as one piece. The tang itself is 10mm wide, and 3mm thick. The Micarta is both epoxied and riveted to the tang bolster and endcap piece. The blade for both knives is then arc welded to the handle bolster construction.