Musashi’s March 2010 starboard photographs show the funnel’s purple shade more clearly in one view than another. Bizen in June 2011 appears lighter, perhaps through camera effect; Iwami’s June 2013 port view is dark bluish. The meaning of Y is unexplained: Rosanoski notes the Yusen Building address and Yusen-named logistics businesses without establishing a connection.
Keep the explicit scope label independent; no alias or company identity is inferred.