This black crewneck sweater from Andersen-Andersen is part of their Sailor line.
Andersen-Andersen
Gudrun & Gudrun
Maison Margiela
Auralee
Jil Sander
J.L-A.L
The Row
sacai
Ss25
Berner KüHl
Howlin'
COMME des GARÇONS
Beach Brains
Unlikely