Unexpectedly kind about Scotsman in Stoppard play (6,3)

I believe the answer is:

indian ink

I'm a little stuck... Click here to teach me more about this clue!

'stoppard play' is the definition.
The definition suggests a singular noun which matches the answer.

'unexpectedly kind about scotsman in' is the wordplay.
'unexpectedly' is an anagram indicator.
'about' means one lot of letters goes inside another.
'scotsman' becomes 'ian' (common Scottish name).
'kind' anagrammed gives 'indk'.
'ian'+'in'='ianin'
'indk' placed around 'ianin' is 'INDIAN INK'.

Can you help me to learn more?

(Other definitions for indian ink that I've seen before include "Deep black writing fluid" , "Writing fluid containing carbon particles" , "Draw with this" , "black pigment" , "Maybe part of squid" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.