Propagational Investment Currency SYstem (PICSY) is an interesting new currency system that has the property of value propagation. All tradings are investments in PICSY because of this property.

I propose the reciprocity principle that is "How much you can buy depends on how much contribution to the society you have made". PICSY model looks like Google?s PageRank [1]. The stable state of the Markov process is intepreted as a society member?s own contribution to the society, provides him the buying power. Normal electronic currency is the extension of non-electronic currency. PICSY differs as it has to use the matrix calculation. PICSY is the first electronic currency which is necessary from its nature.

Settlement Currency SYstem (SECSY named by Asahi Nishikawa) is the opposite of PICSY and just a normal currency. After the trade-off between goods and money we clear the relationship in SECSY. In PICSY we don?t clear the relationship and the seller?s buying power depends on the buyer?s subsequent actions.

The effects of PICSY are productivity growth, rise of fairness, virtualization of organization and transformation of communication. We try to apply PICSY to money in online-game, personnel evaluation in companies and rating systems in a net community.

I propose other similar currency systems besides pure-type PICSY. They have advantages for network decentration and computational effort.