Reversal Engulfing Patterns What is an engulfing pattern? What are the rules regarding these patterns and what are the implications? The patterns can be either bullish or bearish.
There are certain rules that apply to them I use who I consider the most comprehensive source on candlestick charting - Steve Nison to supply the rules and implications Identification Rules Steve Nissan's, Japanese Candlestick Charting Techniques, Second Edition, New York Institute of Finance, 2001.

1. The market has to be in a clearly definable uptrend (for a bearish engulfing pattern) or downtrend (for a bullish engulfing pattern), even if the trend is short
2. Two candles comprise the engulfing pattern.
   The second real body must engulf the prior real body (it need not engulf the shadows).
   
3. The second real body of the engulfing pattern should be the opposite color of the first real body.
   (The exception to this rule is if the first real body of the pattern is a doji.
   Thus, after an extended fall, a doji engulfed by a very large white real body could be a bottom reversal.
   In an uptrend, a doji enveloped by a very large black real body could be a bearish reversal pattern).
   

Factors Increasing Probabilities Some factors increasing the likelihood that an engulfing pattern could be an important turning signal are:

1. If the first day of the pattern has a very small real body (i.
   e.
   a spinning top) and the second day has a very long real body.
   The small first real body candle reflects a dissipation of the prior trend's force and the large second real body proves an increase in force behind the new move.
   
2. If the engulfing pattern appears after a protracted or very fast move.
   A fast or extended move creates an overextended market (either overbought or oversold) and makes it vulnerable to profit taking.
   
3. If there is heavy volume on the second real body of the pattern.
   

What Signals a Failure? So now that we know what an engulfing pattern is and what increases the probablities of a success in the pattern, what indicates the pattern has failed?

1. The highs (in a bearish engulfing pattern) becomes resistance for any further advance (based on a close in price).
   In other words, the prices should not trade over and above the high of the engulfing day bar and close there.
   If they do, the pattern is violated.
   The opposite is true for a bullish engulfing pattern.