Old country is, by Asian reassessment (9)

I believe the answer is:

abyssinia

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'old country' is the definition.
(historical name for Ethiopia)

'is by asian reassessment' is the wordplay.
'is by asian' anagrams to 'ABYSSINIA'.
Though, I am not clear how this is indicated.

Can you help me to learn more?

(Other definitions for abyssinia that I've seen before include "former African state" , "Former name of Ethiopia" , "Former nation" , "What became Ethiopia" , "Former name of northeast African country" .)

I've seen this clue in The Daily Express.

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