A sword still has within its design the point of a spear. There are applications in which the sword is a spear. A knife, too. Same thing. The tsuki is a spiral thrust and can be executed with a spear, sword, knife or even ball point pen. It's the same. And even effective movements that may appear externally linear are still spirals.
Yes, a knifehand strike (tegatana) can be used to cut, but also to strike, and all are spirals.
The sword is generally meant to cut or thrust into soft areas. The jo strikes hard areas - but can also thrust into soft areas. And even though the targets may be slightly different, the movements are exactly the same. A jo is also a spear. A jo is also a sword, because the power sent through the jo can cut through - it doesn't just stop. It's all the same thing.
Tsuki with the hand, sword, jo, McDonald's french fry, chopstick, fork, flashlight, toothpick, tv remote - is all the same. And it is also the same movement within gote kaeshi, iriminage, and tenchinage. All these tsuki movements operate through the front/back direction of the body. Not only uke's, but nage's too. It's the same.
Thanks for the explanation Dan.
A sword does indeed have a point and it's there for times when using it like a spear or even the point of a knife as you rightly say.
I prefer to point out how they are not the same myself and still fail to see which aspect of itself is 'all the same' by your explanation. It seems like you are aware of something which is all the same but I am not seeing it.
A pointed instrument pierces and a weapon with that as its main construct is so used be it a spear, a bullet, an arrow etc.
An edged 'weapon' with that as it's main construct is used for cutting be it a sword, a knife, a saw, or even a circular saw for that matter.
A staff or Jo as a 'weapon' has no point or edge as it's main construct but does as it's main construct have length and natural centre. So primarily used for turning but very interestingly can be used for the other two very easily. So it is more interchangeable in it's use.
I don't see how they are all spirals either myself.
I like your view on through and personally have that as vital point to understand.
So if the thing you are talking about as all the same is spirals then I would hold that as an interesting view, that's fine, but definitely not mine so yet to understand that viewpoint.