A hammer at the bottom of a sell-off and a pin bar look almost identical, small body, long wick, and that's because a hammer is a pin bar with a job title: it only earns the name when it shows up after a decline, at a spot where a reversal would actually make sense. Same shape, different address, different meaning.
The wick logic behind both shapes
A hammer has a small body near the top of its range and a lower wick at least twice the body's length, with little to no upper wick. It forms after sellers push price down hard, then buyers step in and reclaim most of the session's losses by the close. A shooting star is the same idea flipped: small body near the bottom, long upper wick, buyers push price up and sellers reclaim the ground. In both cases the wick is a record of a failed attempt: one side tried to extend the move and got overpowered before the close.
Where they need to appear to mean anything
A hammer needs to show up after a real decline, not just a random red candle. Gold falling from 2,440 to 2,395 over five sessions, then printing a hammer with a $9 lower wick right around a prior support zone near 2,395, is a hammer worth respecting. A hammer-shaped candle appearing after one quiet down day in an otherwise flat market is just a candle with a long wick; there's no exhausted selling pressure behind it to reverse. The same logic governs shooting stars at the top of rallies, EURUSD running from 1.0780 to 1.0870 over a week, then a shooting star forming right at 1.0870, a round number with a prior swing high sitting nearby.
Being honest about the odds
Neither shape wins anywhere close to every time, even in good locations. Studies of candlestick reversals generally find single-candle patterns correct somewhere in the 50 to 60 percent range at recognized levels, and closer to a coin flip away from them. That's not nothing, especially with a favorable payoff attached, but it's a long way from reliable. Treating a hammer as proof the bottom is in, rather than as one piece of probabilistic evidence, is how traders turn a modest edge into a losing habit through oversized confidence. A single stopped-out hammer is not proof the idea was wrong either. It only becomes information once you have a real sample, twenty or thirty of them, tracked in a journal the same way any other setup gets tracked.
Structuring the trade around the uncertainty
Because the edge is modest, the trade needs to be small and precisely defined. Entry sits near the close of the hammer or shooting star, stop just beyond the wick's extreme, below the hammer's low, above the star's high, because that's the exact point that disproves the rejection. On a $10,000 account, a hammer on gold with a stop $6 beyond the wick, at $100 per dollar move per standard lot, sizes to roughly 0.17 lots under the 1% rule. Small size on a modest-odds pattern isn't caution for its own sake; it's matching the bet to the evidence.