This paper is the first one of scientific reports on Tsui-shu (wooden, urushi lacquered and engraved) cameras. These were made and used in the last days of the Tokugawa shogunate. It was considered that three sets of this kind of cameras were in existence. But today, we can see only two. The authors show X-ray computed tomograms of the camera kept in Fukui Municipal Museum of History. Coating layer on the outer surface of the wooden camera body was estimated at 6 mm thickness in maximum. Hg and Fe were detected by means of fluorescent X-ray spectroscopic analysis, as metal element components contained in the layer. It was observed that the painted crust composed of a thin coated reddish pigment-urushi lacquer layer on a heavy coated and reliefed clay-urushi layer, by means of soft X-ray photography and low magnification micrography. Computed tomograms also showed that the optical system of this camera was composed of only two pieces of single lenses and had about 17 cm of focal length. The F-number was estimated at about 7. The first lens was almost a flat plate and the second was in plano-convex type. UV-visible spectrogram showed that the former was made of glass, not quartz. It was considered that the Tsui-shu Camera was made in Japan, not in China, because of following reasons: 1) an imitative “tsui-shu” and Japanese style wooden craft, 2) the optical system, and its cloisonne wared lens cap and the outer cylider were prepared in Owari area of this country.
