He’d often check blue pens make the grade (7)
I believe the answer is:
spassky
'he'd often check' is the definition.
The definition suggests a singular noun which matches the answer.
'blue pens make the grade' is the wordplay.
'blue' becomes 'sky' (sky blue is a shade of blue).
'pens' is an insertion indicator (inserted letters are held or penned in).
'make the grade' becomes 'pass' (I've seen this in another clue).
'sky' going around 'pass' is 'SPASSKY'.
Can you help me to learn more?
(Other definitions for spassky that I've seen before include "one renowned on board" , "He has often checked" , "Russian world chess master in early 1970s" , "prime mover?" .)