Earlier quoted context omitted.
I've been mulling the cause and effect mentioned in your comment. Poor quality steel -> heavy -> 2 handed. I don't ever recall seeing a 2 handed bronze sword, and if the steel is worse than bronze, why didn't they go back to that? Which kind of suggests that it isn't. I'm assuming low quality steel is overly soft rather than overly brittle. If it were overly soft wouldn't that favour shorter blades? You'd either get…
>I got the impression 2 handed swords/no shield was an honour thing, rather than a tactically advantageous thing, I'm in no way an expert on such things though. I am not an expert either but as I understand it, Samurai were nobles and fought on horseback with their primary weapons being spears and bows, and they considered swords a backup weapon.[0] The mythologizing of the Samurai, their honor-above-reason mentality…
Agreed, I was focussing more on the not tactically advantageous, rather than ascribing an honour code per se.
It is generally a good idea to agree weapons beforehand, it helps keep the battlefield survivable. The 20th century wasn't known for it's 'honour' but WW2 combatants did refrain from using chemical weapons for example, and nukes were never used in the cold war and it's proxy battles. I'd label that as part of an honour code? I'm not making the case too forcefully though.