Heading to Japan, one's to bring in black sails (4)

I believe the answer is:

jibs

'sails' is the definition.
(jib is a kind of sail)

'heading to japan one's to bring in black' is the wordplay.
'heading to' says to take the initial letters.
'one's' becomes 'is' (roman numeral**).
'to bring in' is an insertion indicator.
'black' becomes 'b' (as in pencil classifications).
The initial letter of 'japan' is 'j'.
'is' enclosing 'b' is 'ibs'.
'j'+'ibs'='JIBS'

I've seen this clue in The Independent.

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