Strength needed to follow black dog (6)
I believe the answer is:
basset
'dog' is the definition.
(basset is a kind of dog)
'strength needed to follow black' is the wordplay.
I cannot quite understand how this works, but
'strength' could be 'asset' (I've seen this before) and 'asset' is found in the answer.
'black' could be 'b' (as in pencil classifications) and 'b' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for basset that I've seen before include "Short-legged hound that hunts hares" , "Type of hound" , "Hound (named Fred?)" , "Hare-hunting hound among beasts" , "Short-legged dog" .)