For the most part the hallstatt and leaf style blades are the most popular. What of the Carp's tongue blade. Who used these blades, Oakeshott wrote "may have been in S.Britain" but finds all over even one at Paris. Why the narrowing? Penetrate armor,was only bronze age or like a boar sword to only go so deep as to kill and still be able to pull sword out? I did google but mostly fish came up.

Aren't they interesting? They were even used in Sardinia. I doubt we can determine the "why" of that shape, but it's not for armor-piercing. There wasn't much armor to pierce, and swords aren't made to do that sort of thing anyway. More likely, the shape has an affect on balance that was desirable. Or maybe they just thought it was cool!

Matthew