Japanese old gun researchers say that 'matchlock guns in Sri Lanka' exhibited in the Portugal Pavilion of Tsukuba EXPO was 'Sakai tsutsu (hinawaju made in Sakai) for export' which was a Japanese gun that had a gunstock decorated with marquetry, the locals' favorite, which is considered as historical material supporting the theory.
つくば科学万博においてポルトガル館で展示された「スリランカの火縄銃」は、日本製の銃に現地好みの木象嵌を銃床に施した「輸出仕様の堺筒」であるとの見方が日本の古銃研究家の間から出されており、この説を裏付ける資料とされる。