Body of soldiers in Saigon manoeuvred to protect both sides of river (8)
I believe the answer is:
garrison
'body of soldiers' is the definition.
'garrison' can be an answer for 'body' (I have seen 'Body of troops ' mean 'garrison' so perhaps 'body' could also mean 'garrison'). I am not sure about the 'of soldiers' bit.
'saigon manoeuvred to protect both sides of river' is the wordplay.
'manoeuvred' indicates anagramming the letters.
'to protect' indicates putting letters inside (inserted letters are protected or taken in).
'both sides of' means to remove the middle letters (only the letters on the sides remain).
'river' with its middle taken out is 'rr'.
'saigon' is an anagram of 'gaison'.
'gaison' going around 'rr' is 'GARRISON'.
'in' is the link.
Can you help me to learn more?
(Other definitions for garrison that I've seen before include "Provide (place) with troops for defence" , "(Soldiers guarding) fortified place" , "Fortified military post" , "army base?" , "An armed force - or its location" .)