That's fascinating. I'm accustomed to a certain vibration in European style swords, wether they're steel or aluminum (aircraft aluminum, to be specific). An arming/knightly sword, when you smack the pommel, will produce a vibration that travels up the blade. There will be two spots that the wave terminates. One is about 3 inches (or so) below the very tip of the blade, and the other (ideally) is in the grip. That "sweet spot" near the tip is the place where the cut should land, and a blow struck there transfers no (or very little) vibration to the hand.
Yes, it's true that aluminum trainers cannot be as thin or shaped as steel. It's still a much softer metal and should be treated as such. My own sword, while well balanced, is still heavier than the few antique swords I've been fortunate enough to handle. Those ancient blades feel like lightsabers in comparison. It's a compromise for safety since it doesn't sport an edge of any kind. I still like it because it conditions my weak and flabby body.
So, in comparison, a Japanese style blade should not exhibit any kind of flex or vibration at all?
Yes, it's true that aluminum trainers cannot be as thin or shaped as steel. It's still a much softer metal and should be treated as such. My own sword, while well balanced, is still heavier than the few antique swords I've been fortunate enough to handle. Those ancient blades feel like lightsabers in comparison. It's a compromise for safety since it doesn't sport an edge of any kind. I still like it because it conditions my weak and flabby body.
So, in comparison, a Japanese style blade should not exhibit any kind of flex or vibration at all?