Dark Cloud Cover

The pattern starts with a green candle followed by a gap up. The gap up shows potential buyer strength for continuation at open.

The gap up is met with selling pressure, with sellers closing the second candle red and below the first green candle's 50% control point (halfway between the open and close). The 50% control point is a very commonly used, and powerful way of measuring who is more dominant in the market.

With sellers pushing price below the 50% CP and holding below into the close, this shows you that sellers have potentially begun to overpower buyers in this market.

Like its bullish counterpart, the piercing line, this pattern is significant because the previous candle's midpoint is seen as a point of control. If buyers are able to maintain price above the midpoint, then you can say that buyers are still in control. With a dark cloud cover, after the gap up on the second day, sellers are able to reclaim the midpoint, showing that they potentially are reclaiming control of the trend.

Another example, starting with the daily timeframe and then zooming into an intraday timeframe to see how price interacts with the midpoint.

On the intraday timeframe, halfway through the day, buyers tried holding above the midpoint with a hammer, but ultimately failed as sellers took control.