China. (Hong Kong - Thailand). 1939. Registered Air Mail envelope addressed to Amsterdam, Netherlands bearing SG 430, $2 brown tied by Shanghai date stamp '13th Oct 39' with matching registration label, endorsed 'via Hong Kong/ Bangkok and per K.L.M.' with 'Registered/ Hong Kong' transit on reverse '18th Oct and Amsterdam receiver '2nd Nov'.
Lovely single franking sent 'K.L.M.' via Bangkok.