Eric (and all): According to records from the British Public Records Office, (Ref.: WO 208/1604 110711), held in N.E.I. Tech II file, "300 anti-tank guns (20-mm) were delivered to Holland for the N.E.I. from Solothurn in September 1938, and a futhrer 500 A.T. guns of unknown calibre were ordered from Solothurn towards the end of 1938. Early in in 1940 38 cases of anti-tank machine guns of unknown calibre were shipped from Italy." This was signed by "Lieut.-Colonel, G.S.", apparently from M.I.2, dated October 19, 1940. I could find nothing resembling the piece in the photo in "Catalogue of Enemy Ordnance Mateiel, Volume II -- Japanese" published by the Ofice of the Chief of Ordnance (U.S. Army) (no date).