The Downside Gap Three Methods Bullish is a bullish reversal pattern represented by three candles.

During a downtrend, the first candle decreases and has a long body. The second candle, still decreasing, opens below the low of the previous one, then featuring a gap. The third one starts increasing and closes within the body of the first candle.

During a downtrend, two long decreasing candles feature a gap between them. Gaps usually tend to be closed by another candle, and we can see how the third candle closes it with a long bullish movement. The bulls take over the third and last candle, making a long increasing candle that closes above the previous one, and very likely initiates a new uptrend. 

Therefore, this pattern would signal a buy in your strategy.