A very special 'tulwar'

[fernando]

Originally Posted by Kubur

...For me estoc is not a weapon...

I would understand that some forms of estocs are not swords but, they are certainly weapons.

Originally Posted by Kubur

...It's a way of striking an opponant...

There could be a question of terminology depending in the various languages but, "estoc" would be the weapon, a strike (blow) with it, would be an "estocada".

Originally Posted by Kubur

...But even the rapiers used for the estoc have sharp edges...

Perhaps not all had or needed sharp edges; it is a question of going back in time, when the true rapier was a long, narrow, rigid, nearly edgeless single-hand thrusting blade with a thick, tapering cross-section and very narrow and sharp point.
And if you go further back in time, prior to rapiers, you would find that, there were special Medieval thrusting swords, called estocs or tucks which were used since the 1300s. They were large, heavy, stiff, two-handed blades specifically designed to puncture or beat on plate armor. They were not handled like rapiers but are directly related to the use of Medieval swords held by the blade (what was called at the “half-sword”). Yet, it is conceivable that the idea for a rapier could have developed from an estoc or tuck.
They had many names in different countries and were essentially just sharp metal rods with square or triangular cross-sections and typically two large, round hand guards.
(Part of the above, courtesy of Arma Association)