TAU proposes a fast circulation currency without inflation. Users collectively grow and secure the network by doing commoner's behavior-transactions. With the technology innovation of "Proof-of-Transaction", users with transaction history are incentivated by sharing the future block reward. No advantage is for concentrating wealth and hardware as in POS and POW. Low barrier to coins, voting and rewarding for commoners are TAU inplementation of fairness. Different from other systems, TAU aims the more transaction abundance, the higher speed and the lower total cost. ICO plan: TAU foundation will allocate 60,000 TAUcoins into ICO pool once every 360 blocks, about 6 hours. Investors receive TAUcoins by their portion of BTC investd to the total BTC received during the timeframe. In the case of no investments, the unattended coins will be added to the next ICO time frame.