A wide up candle followed by a small down candle contained entirely within it. Not a reversal so much as a sudden stop — the advance simply ran out of momentum.
The second body must sit inside the first body's range. After a strong up day, a narrow quiet session says buyers did not follow through, which is worth noticing even though sellers have not yet taken anything back.
Read it as deceleration rather than a turn. It is the weaker sibling of the bearish engulfing, where sellers actively erase the previous day.
The smaller the second candle relative to the first, the sharper the loss of momentum. A second candle nearly as large as the first barely qualifies.
It fails frequently. A pause after a strong day is normal behaviour in a healthy uptrend, and many haramis resolve upward once the pause ends.
Narrow low-volume days cluster around holidays and expiry weeks for reasons that have nothing to do with sentiment.
Confirmation is essential. Without a following close below the harami's low, the pattern describes a quiet day and very little else.