The ABCD is a basic harmonic pattern. All other patterns derive from it. The pattern consists of 3 price swings. The lines AB and CD are called “legs”, while the line BC is referred to as a correction or a retracement. AB and CD tend to have approximately the same size. A bullish ABCD pattern follows a downtrend and means that a reversal to the upside is likely. A bearish ABCD pattern is formed after an uptrend and signals a potential bearish reversal at a certain level. The rules for trading bullish and bearish ABCD patterns are the same, you will just need to take into account the direction of the pattern you trade and the movement of the market it predicts.