A simple exchange between two parties of things of equal value isn't capitalism. Both parties gain as much as they lose and therefore do not experience profit.
However, if party B takes the product of A's labor without giving back something of equal value, we have capitalism in the exchange and a state in the reason behind B's privilege. Perhaps it's B's perceived strength or holiness. Perhaps B has the backing of a more powerful authority. Without such a reason, there is no state and A won't consent to such a deal.
You really need to stop and think about what you mean to say, before you type. Capitalism is simply a concept that pulls together several economic laws under one word. Laws in the "natural" and "God created them" kind. The first being, the individual has a right to the fruits of his labor. (i.e. the
capital) and he also has a right to trade it freely without coercion. The value of the two items being traded don't have a set value, the value of each thing is subjective to the perspectives of he who trades. The law of supply and demand also comes into play; as these two could be trading things on the (original) Silk Road, one trading silk from China and the other trading whatever it is that Europe made that Chinese people wanted. Each item is moving from a region that has more of it, and therefore it's market value is lower, to a region where there is less of it, and therefore it's market value is higher. That's called 'arbitridge'. Another law that you don't know is comparative advantage. Go google "the island trading game".
What you think is capitalism, is corporatism, and a far cry from capitalism. A free market, by definition, is capitalist in nature; but that does not mean that capitalism only exists in a free market. As has been noted by another, capitalism exists always and everywhere, it's just illegal under certain political conditions.