Wave One is created by profit taking within the  late stages of a previous Wave 5 or Wave C.  It is usually a weak move against the previous trend with few participants.

Wave One usually consists of a three wave move.  However, it may sometimes be a five wave move.

Once Wave One has completed, the  market will revert to its previous trend  direction. Also, trend following methods  will re-enter the market with hopes of  a return to the extremes of the  previous trend.