A bar with a long shadow and a small body at the opposite end, showing that price probed a level and was rejected.
The name comes from the idea that the long wick lies about where price could hold. A bullish pin bar has a long lower-shadow; a bearish one has a long upper-shadow. Most definitions require the shadow to be two thirds or more of the total range.
Pin bars are the core of many price action systems because they mark a precise level and a precise invalidation: the tip of the wick.
Their honest limitation is frequency versus quality. Pin bars print constantly on low timeframes and most lead nowhere. What separates the useful ones is location at a higher-timeframe level, a wick that took out an obvious prior high or low, and a following bar that does not reclaim the wick. Without those filters, the pattern is close to noise.
Original diagrams for the ideas on this page. Illustrative, not real market data.
The parts of a candlestick. One candle sums up a slice of time: the thick real body runs from the opening price to the closing price, and the thin wicks reach out to the highest and lowest prices traded. Colour tells you which way the body ran.
Educational only, not advice. Spotted an error? Post in Site Feedback.