A Hammer candlestick pattern is a single-candle bullish reversal signal that usually appears at the bottom of a downtrend. It has a small real body (green or red) near the top of the candle and a long lower shadow (at least twice the body’s size) with little or no upper shadow. The long lower wick shows that sellers pushed the price down significantly during the session, but buyers stepped in strongly and drove the price back up near the open, signaling potential buying pressure. While the hammer suggests a reversal, traders usually wait for confirmation from the next candle (such as a bullish close) before taking long positions. Appears after a decline. Long lower shadow = rejection of lower prices. Small body on top = buying strength returning. Next candle confirmation increases reliability.