The Silverflex is a plain copy of the Ricohflex VI. The taking and viewing lenses are externally geared for focusing. The distance scale and depth-of-field indications are engraved on the upper lens. The viewing hood contains a large magnifying lens. The film is advanced by a knob on the photographer's right. The advance is controlled via a red window in the back, protected by a vertically sliding cover. The exposure chamber comes out together with the spool holders for film loading.
The lenses are 80mm f/3.5, and the marking is SILVER ANASTIGMAT on the taking lens and SILVER VIEWER on the viewing lens. The shutter is of the setting type and has flash synchronization. The release lever is attached to the shutter casing itself.
The Silverflex Model S
|Announcement of the Silverflex in Asahi Camera September 1953. (Image rights)|
The Silverflex Model S was first announced in Japanese magazines dated September 1953. The announcement in Asahi Camera says that the manufacturer was known for its Silver Lucky enlargers, and that the Silverflex was its first camera. The document mentions a limited range of shutter speeds (B, 25, 50, 100) and a price of ¥8,500.
Advertisements published in Asahi Camera from September to November 1953, reproduced below, give the same price and characteristics. The September issue contained a special lottery ticket for owners of the Silverflex, offering various prizes, ranging from a Silver Pigeon scooter to a free single issue of Asahi Camera.
|September 1953, with lottery ticket||September and October 1953||November 1953|
|Advertisements for the Silverflex in Asahi Camera. (Image rights)|
The leaflet reproduced below is specifically about the Silverflex Model S, and mentions B, 25–100 speeds. The picture is the same in all the documents. It shows B, 25, 50, 100 speed settings, an ASA synch post and taking lens no.195143C.
|Leaflet advertising the Silverflex Model S. (Image rights)|
The January to April 1954 issues of Asahi Camera have a newer advertisement, displaying a range of cameras by Nippon Kōki. The price is unchanged but the range of speeds is now B, 10–200. In all the advertisements, the camera is only called "Silverflex" (シルバーフレックス) and the full name only appears on the camera's nameplate as SILVERFLEX MODEL S.
|Advertisement in Asahi Camera January to April 1954. (Image rights)|
Some actual examples have an NKS shutter (B, 10–200) with flash synchronization, marked NKS at the bottom of the speed rim and at the top of the shutter plate. Early ones have an ASA synch post, later ones seem to have a PC socket.
There was also a clone of the late Silverflex Model S, which was branded as the Sharpflex Model S 
The Silverflex Model L and Model LII
One example of a Silverflex Model L has been reported, with an S.S.S. shutter (B, 1–200) and lens no.6113. This number indicates that the camera went after Model S. It is likely that the only difference with the previous model is the new shutter with slow speeds.
|Silverflex Model LII, Silver Anastigmat 80mm f/3.5 lens no.6328.|
Pictures by email@example.com. (Image rights)
Finally, the Silverflex Model LII pictured above is the only example of its kind found so far. It has an S.S.S. shutter with self-timer and PC socket. Its features seem similar to the Model L, but for the nameplate inscribed SILVERFLEX MODEL LII.
- On p.443 of Kokusan kamera no rekishi, Orima Isamu (織間勇), who was an engineer at Riken from the 1950s, says that the build quality of the Silverflex was appalling. The same kind of comments also appear in this page by Oozusi.
- Kokusan kamera no rekishi, p.352.
- Column in Asahi Camera September 1953, p.175.
- Advertisement in Asahi Camera September 1953, p.73 (also reproduced in Kokusan kamera no rekishi, p.140), October 1953, p.76, and November 1953, p.35.
- Advertisement in Asahi Camera January 1954, p.187, February 1954, p.75, March 1954, p.51, and April 1954, p.167. It is also reproduced in Kokusan kamera no rekishi, p.140, and in this page at Shashin-Bako.
- See the pictures here at Oozusi's site.
- Example pictured in Sugiyama, item 2255 (lens no.2xxx).
- Example pictured here at Oozusi's site (lens no.4120).
- Sharpflex Model S a clone of the later specification Silverflex S at Camera Portraits.
- Report in this page by JacQ.
- Asahi Camera September 1953. "Shinseihin memo" (新製品, New Products Memo). P.125.
- Asahi Camera. Advertisements by Nippon Kōki:
- September 1953, p.73;
- October 1953, p.76;
- November 1953, p.35;
- January 1954, p.187;
- February 1954, p.75;
- March 1954, p.51;
- April 1954, p.167.
- Nippon Koki Co., Ltd. Silverflex Model S. Leaflet published c.1953, date not indicated. Contains some information on other products by Nippon Kōki, including the Silver Six. Document reproduced in this Flickr album by Rebollo_fr.
- Asahi Camera (アサヒカメラ) editorial staff. Shōwa 10–40nen kōkoku ni miru kokusan kamera no rekishi (昭和10–40年広告にみる国産カメラの歴史, Japanese camera history as seen in advertisements, 1935–1965). Tokyo: Asahi Shinbunsha, 1994. ISBN 4-02-330312-7. Item 536. See also the advertisement for items 537–8 and the interview of Orima Isamu (織間勇) on p.443.
- Lewis, Gordon, ed. The History of the Japanese Camera. Rochester, N.Y.: George Eastman House, International Museum of Photography & Film, 1991. ISBN 0-935398-17-1 (paper), 0-935398-16-3 (hard). P.82 (brief mention only).
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover). P.721.
- Sugiyama, Kōichi (杉山浩一); Naoi, Hiroaki (直井浩明); Bullock, John R. The Collector's Guide to Japanese Cameras. 国産カメラ図鑑 (Kokusan kamera zukan). Tokyo: Asahi Sonorama, 1985. ISBN 4-257-03187-5. Item 2255.