Kansas KSA 21-4201
21-4201. Criminal use of weapons. (a) Criminal use of weapons is knowingly:
(1) Selling, manufacturing, purchasing, possessing or carrying any bludgeon, sandclub, metal knuckles or throwing star, or any knife, commonly referred to as a switch-blade, which has a blade that opens automatically by hand pressure applied to a button, spring or other device in the handle of the knife, or any knife having a blade that opens or falls or is ejected into position by the force of gravity or by an outward, downward or centrifugal thrust or movement;
(2) carrying concealed on one's person, or possessing with
intent to use the same unlawfully against another, a dagger, dirk, billy, blackjack, slungshot, dangerous knife, straight-edged razor, stiletto or any other dangerous or deadly weapon or instrument of like character, except that an ordinary pocket knife with no blade more than four inches in length shall not be construed to be a dangerous knife, or a dangerous or deadly weapon or instrument;
Statutes
Basic weapons law is 21-4201, concealed weapons law is 75-7c, use of force is 21-3211,2112,3213.
You can have a Ninja sword on your desk as a letter opener and slice a burglars head off with it, but you can't carry a straight razor unless you are a barber.

The point is somethings are illegal in themselves [often silly reason, like a KungFu movie scared a legislator, so a butterfly knife is illegal] [clack, clack:aargh4:]
No your state;s law and where you travel.