A hammer appears after a strong downtrend, its appearance of a short body with
a long bottom tail signifies that selling pressure has weakened. Sellers
were able to pull the price down but bounced back higher than its opening price
at the end of the period, during a long downtrend, the further down the price
goes, the greater pull pressure it requires to sustain it. This is due to short
positions being closed out to lock in profit from that long downtrend.
A hangman indicates that the buying pressure is weakening, the price went up
as high as it could only to drop significantly as buyers either closed out their
positions or sellers took over in full force. A hangman looks like a hammer,
but it appears after an uptrend.