I wish I had some ultimate currency

ultimate currency is the type i can use anywhere in the world :P

ultimate currency = gold. In practice, everything is valued in relation to the value of gold. conventional currency = the currency or currencies used in trade in a particular country or area. In China that would be CNY. In South China it is possibly CNY and HKD. Here in Vietnam it is VND and USD. That is, you can trade in either VND or USD. Border towns usually have more than one type of conventional currency (for obvious reasons).