Japanese External Reverse Porro Prism Binoculars. On Line MUSEUM |
Though it now has major sections of military binoculars (OTHER BINOCULARS sections) and full size binoculars (BIG & SMALL sections) this website was created to document “miniature binoculars”: small reverse porro prism binoculars with form fitting external prism covers , also called “M Type” (Mikron Type), skeleton, mini, vest pocket, micro binoculars, etc. First developed in Germany in 1919, these binoculars were produced in limited numbers in Japan between the wars, produced during/ after the WWII US occupation of Japan, and were widely distributed as a luxury item under a great may brand names. Most of the Japanese contract manufacturers and trading co/ exporters involved were small and went out of business many decades ago. Information about them has been scarce. I have conducted thousands of hours of original research; and documented brands; powers produced; manufacturers, and distribution. This website allows me to share that information. Having “hands-on” experience with over 1,100 of these binoculars, most now have seized oculars due to age hardened optical grease, or prism collimation/ displacement, and other issues. So after repairing around eight hundred +, I created instructions on repairing miniature binoculars to help mechanically inclined optical enthusiasts repair/ restore their miniature binoculars. The nature of the Japanese binoculars industry was that groups of assembling contract manufacturers produced binoculars with parts they made or bought from sub manufacturers, acting under contracts with exporters & trading companies & and foreign importers & distributors & and retailers. With very few exceptions, all of the binoculars brand names you are familiar are distributor or marketing and not manufacturer names. This applies to binoculars branded as Bushnell, Swift, Jason, Tasco, Selsi, Kalimar, Sears, Tower, Milo, Sans & Streiffe, Focal, Frank Nipole, LL Bean, Boots, Imperial, Brookstone, Compass, Empire, Sears, Wards, Scope, Yashica etc. Almost every brand was made by many different manufacturers, and almost every manufacturer marked binoculars with many brands. There are only a few exceptions where manufacturing companies also directly controlled aspects of their own product production, marketing, and distribution (Nikon, Asahi/Pentax, RKK); sometimes with distribution through licensed subsidiary or affiliate importers and distributors. For miniature binoculars I have identified over 32 actual primary assembling manufacturers, though many other companies made small parts. And specific models of specific brands were sometimes made by many multiple manufacturers at different times. Just for example, I have PERSONALLY observed miniature binoculars made by just ONE prolific manufacturer Seiwa Kogaku Ltd./ Seiwa Kōgaku Kōgyō Kabushiki-geisha / 清和光学株式会社 ( mfgr. code JB93 ) to be sold as these brands, and this is just during the period mfgr codes were marked (Updated 3/11/2021). |
MFGR. JE CODE ON FRAME (common), (JE50 metal parts manufactured by Tanaka Koki Seisakujo. Inc. |
MFGR. CODE ON HINGE COVER (less common placement of marking) J-B231/manufacturer Tochihara Optical Co |
MFGR. CODES “HIDDEN” ON INTERIOR PORTION OF PRISM COVER (common) JB74 assembling manufacturer Omori Sogo Kogaku Kogyo, J-E51/ metal parts Yoshimoto Kogaku Co. |
Manufacturer Codes on Japanese Binoculars . Hersteller-Codes auf Japanischen Ferngläsern. Codes Fabricant sur Jumelles Japonaises. 日本 の双眼鏡メーカーコード. коды производителей на бинокль из Японии. Tillverkarkoder på Japanes Kikare. Códigos de Fabricante en Prismáticos de Japón. Codici del Costruttore sui Binocoli Giapponesi. |
Logos of Japanese Binocular Manufacturers. Logos der Japanischen Ferngläser Hersteller. Logos de Jumelles Japonais Manufacturiers. Логотипы японских биноклей. 日本 の双眼鏡メーカーのロゴ. Logos av Japanska Kikare Tillverkare. Logos van Japanse Verrekijkers Fabrikanten. Logos de Prismáticos Japoneses. Loghi dei Costruttori di Binocoli Giapponesi. |
MFGR. CODE “NOT HIDDEN” ON EXTERIOR PORTION OF PRISM COVER (less common placement of marking). J-B69/manufacturer, Akebono Kogaku Kogyo Co |
L |
J |
THE “J-B” above or “JB” mark is actually combined letter JL plus B, as represented above, meaning “Light Machinery of Japan”. |
MARK OHNO |
There is sometimes a way to know the actual manufacturer, by a stamped or rotary engraved manufacturer’s code, when present, as explained below and shown in the pictures |
“ K ” logo trademark of Omori Sogo Kogaku Kogyo |
Prior to, during, and after, the JB and JE codes were commonly being marked, one can sometimes determine the manufacturer of some of these binoculars by a stamped logo that contains no wording. In some cases it is easy to know what company these logos indicate. For example, the “ K ” logo of Omori Sogo Kogaku Kogyo on the right is very frequently seen. There are other logos that are not so commonly known or referenced. See our page TRADEMARKED LOGOS for the period applicable trademarks Peter Abrahams documented plus a few others I documented from sources like WIPO and TESS . |
According to Peter Abrahams in Outline of Japanese Binocular Production from Nov 1959 and for roughly 30 years disclosure of manufacturer was mandated/ encouraged on optical products, and binoculars, as part of a quality approvals scheme (those oval “passed” stickers by the Japan Binoculars Export Promotion Association). But my experience examining 1,100 +miniature Japanese binoculars suggests the mfgr code marking tapered off in late 1970’s. Mfgr. marking consisted of a combined letter JL (for light machinery of Japan) which in reality looks like J- plus letter B or E, plus a number. So a “J-B” code stamping is for the “assembling manufacturer” of the binoculars, and a “J-E” code stamping is for the manufacturer of the metal frame/body. Binocular collectors refer to these as “JB” and “JE” codes. Around 1955 the Japan Export Binocular Industry Assn imposed production limits (allocations or quotas) as well as price and quality controls on Japanese binocular manufacturers, because of production quantity exceeding demand. According to Abrams, in Aug 1960 the Japan binocular Export Projects Association was created to purchase and export binoculars, but it collapsed in Mar. 1961 with a huge overstock of binoculars, and most of the 203 Japanese binocular manufacturers in operation in 1959 had gone out of business by 1961. Documentation who made what, and what brands were tied to what distributors 40 and 50 years before the internet, had been quite scarce, and to the degree that it existed at all, perhaps not on the internet in English. Some important reference materials in the past had been documented by Bill Beacom, Fred Schwartzman, and Peter Abrahams (see JB JE MFGR. CODE LIST section). |
Confusing Names of Japanese Companies Selling Binoculars Verwirrung Namen von Japanischen Firmrn, die Ferngläser Verkaufen. Confondre les Noms des Enterprises Japonaises. Qui Vendent des Jumelles. Смутные имена Вариации японских биноклей компаний. わかりにくい名前日本の双眼鏡のバリエーション企業. Förvirrande Namn på Japanska Företag som Säljer Kikare. Nombres Confusos de las Empresas Japoneses qui Vendieron Prism á ticos. Confuso Nomi di Aziende Giapponesi che hanno Venduto il Bonocolo. |
One of the difficulties in discussing and researching Japanese optical (Kōgaku) companies (manufacturers, trading co’s, exporters, purchasing agents, distributors) is that there are multiple variations of each company name: the name using a combination of Chinese derived Japanese characters (kanji) and Japanese characters (kana); the same name using the western alphabet (rōmaji); and then the same name in one or more “translated” forms where words are presented in some loose English equivalent. Additionally there are company name changes over time. Using Riken as an example, in kanji it is 理研光学工業㈱ . In rōmaji and partially abbreviated it is Riken Kōgaku Kōgyō K.K, or unabbreviated is Riken Kōgaku Kōgyō Kabushiki-kaisha (or-Kabushiki-gaisha). In “translated” form it may be Riken Optical Industries Co., Ltd. And then like many other Japanese optical companies, Riken renamed itself and became Ricoh, which in kanji is 株式会社 リコー , and in rōmaji is Kabushiki-kaisha Rikō or Kabushiki-geisha Rikō, and in “translated” form may be Ricoh Optical Industries Co., Ltd, or several other variations. Additionally manufacturers often had an associated controlled “trading “ entity with another name. For example the manufacturing entity Toyo Jitsugi Kōgyō Kabushiki-Kaisha also had the associated Trading entity Oriental Trading Co. “ TJK ” for T oyo J itsugo K K appears on binoculars, but so does “ OTC ” for O riental T rading C o. Oriental Trading Co in acting as a purchasing agent/trading co. might handle binoculars made by other factories in addition to its own manufacturing entity, and Toyo Jitsugo as a manufacturer might sell binoculars through other entities than its own trading co. And while ownership was largely the same, there were some different stockholders. Back to Riken: in discussing Riken any one of nine or more variations of their name might be correct to use in discussing a pair of binoculars that the company produced or handled, or any variation might appear in reference materials you are searching. In addition, an alphabetic company logo or abbreviated acronym might have been used based on any of these variations. In the case of Riken, they used RKK and R.K.K. based on the rōmaji abbreviation of Riken Kōgaku Kōgyō d uring the time that they made these small binoculars. (In general I try to cite the rōmaji names used at the time the binoculars was made). One commonly finds Kōgyō K.K. as a part of the name of these Japanese optical company names. This stands for Kōgyō Kabushiki-Kaisha, (which may also be equally correctly spelled Kabushiki-gaisha), with Kōgyō roughly translated as “industries” and K.K. representing either Kabushiki Kaisha or Kabushiki-gaisha, which may be translated as “industries” and “company, Ltd .”, but may also be translated as “corporation” or “incorporated” or “joint stock co”, but without really being exactly the same business structure as would be for a company using those terms as legally defined ones in the USA. Sometimes Seisakujo is substituted for Kabushika-geisha, and Seisakujo roughly means “factory”, which, as in English, is more of an informal description than any specific legal business structure. It is therefore possible to interpret two Japanese co. name variations as being separate entities when they are not, but is also just as easy to interpret identical or nearly identical entities as being the same when they are unrelated. For example there was a Seiwa Kogaku Co. Ltd (which translates as Seiwa Optical Co Ltd.) that was completely unrelated to another entity called Seiwa Optical, Ltd. And there was an Asahi Kogaku K.K. that made cameras and binoculars (and became very well established and eventually morphed into Pentax) and there also was a completely unrelated entity also named Asahi Kogaku K.K. that made cameras and faded into obscurity, and a third company involved in binoculars names Asahi Kogakuki Co Ltd completely unrelated to the other two. Likewise there were at least four unrelated Japanese binocular manufacturers whose Romanji names spelled out K.O.C. and who were known to have used K.O.C. on markings on binoculars . So what K.O.C. signifies depends entirely on contextual subtlety. And the company associated with miniature binoculars using “ KOC ”, K uroki O ptical C o. is known to have additionally used ‘ KOIC ” for K uroki O ptical I nstrument C o at a slightly different point in the company history. |
Miniature Binoculars Model Number. Miniatur-Fernglas Modellnummer. Numéro de Type des Jumelles Miniatures. Номер модели. Miniatyr Kikare Modellnummer. Miniatura Prism á ticos Números de Modelo. |
Only a few of these small binoculars display model numbers on the prism covers. Since almost all have serial numbers, the serial numbers are often confused with being model numbers. Model numbers are usually written as “ Model” or “mod” or ”M” then “No.” and then the number. Einige dieser kleinen Ferngläser haben Modellnummer auf den Prismaabdeckungen. Fast alle diese Ferngläser haben Seriennummern. Die Seriennummern werden häufig mit Modellnummer verwechselt. Modellnummer werden geschrieben normalerweise als „Model“ oder „Mod“ oder “M”, dann „No.“ und dann die Zahl. Quelques jumelles affiche des numéros de type sur les couvertures de prisme. Comme presques toutes ont les numéros de séries, les numéros de type sont souvent confondus avec les numéros de serie. Les numéros de types sont souvent prefixe par « Model » ou « Mod », ou « M », avec ou sans « No. ». |
Miniature Binoculars Serial Numbers. Miniatur-Fernglas Seriennummer. Numéro de Série des Jumelles Miniatures. Орядковый Номер. Miniatyr Kikare Serienummer. Miniatura Prism á ticos Número de Serie. |
“Reverse Porro Prism ”. Rückwärts Poro Prisma. Jumelles Prisme Inverse de Porro. обратная призма. 逆 ポロプリズム. Omvänd Poro Prisma. Omgekeerd Porro Prisma. Prisma de Porro Atrás. Prisma Porro Inverso |
Reverse porro prism binoculars arrange the prisms in a configuration so that the image transmission reverses itself twice, allowing a particularly compact design package. Diese Ferngläser haben Prismen, das den Weg des Lichtes zurück auf sich zweimal dreht. Ces jumelles ont des prismes qui renverse le chemin de la lumière deux fois |
In some languages and at various points in times these small binoculars have been referred to in a number of ways. They are often referred to in English as “miniature binoculars”, or as micro or vest pocket or pocket or compact or sub compact or mini or spy or skeleton binoculars, or less correctly as opera glasses (true opera glasses are non prismatic). They may also be referred to as field glasses or theater glasses. German nomenclature is also complicated, and subtleties of meaning today might have been less so in the past. For example, while the German “prismenfernrohr” might accurately today only refer to a prismatic type telescope, in the past Zeiss and others sometimes referred to binoculars that way. These small binoculars may be referred to in German as “Fernglas”, “Ferngläser”, “Opernglas”, “Opergucker”,“Feldstecher”, “Prismenglas”, “Theaterglas”, “Fernrohr”, “Mikrofeldstecher”, “Zwergferngläser”, “Prismenfernrohr” or even “Operngucker Skelettfernglas” or “Mikrofeldstecher”. It makes a Google® search for these in German “challenging”. In Swedish these may be “Miniatyrkikare”, and many languages have various potential sub categories to define these beyond the basic term for “binoculars”. |
Ambiguous Nomenclature. Viedeutiges –Nomenklatur. Nomenclature Ambigue. вусмысленным названия компаний. Tvetydig Nomenklaturen. Nomenclatura Ambigua. |
Serial numbers on the prism covers. Seriennummer auf der Prismaabdeckung. On trouve les numéros de série sur la couverture du prisme. |
Serial number on the frame |
Almost all of these small binoculars have serial numbers. On some of the earliest it is on the frame. On post war versions it is normally on a prism cover. Though sometimes confused with model numbers, the serial number is usually longer, and is usually is written as “No.”/ “Nr.” and then the number. Die meisten dieser kleinen Ferngläser haben Seriennummern. Die Seriennummer ist normalerweise auf der Prismaabdeckung. Es wird als „No“/ “Nr.” und dann die Zahl.La plupart de ces petites jumelles ont des numéros de série. Il est normalement sur la couverture de prisme. Cependant parfois confus avec des numéros de type, le numéro de série est plus grandque le nombre de type et est préfixe par « No. / “Nr.”». |
Quality Inspection: Binoculars. Qualitäts-Inspektion Fernglas. Inspection de Qualité des Jumelles. Проверка качества.Бинокль. Kvalitesontroll av Kikare. Inspección de la Calidad de Prismáticos. Ispezione di Qualità del Binocolo. |
The flyer at right came with one of these binoculars and explains the Japanese “quality” inspection by the JTII (Japan Telescopes Inspection Institute), a quality control organization for optical products being exported from Japan. Various alternative “inspection arrangements” also existed. |
Power (Magnification) of Binoculars. Leistung Im Sinne De Ferngläser. Puissance d’optique des Jumelles. оптических измерений мощности на бинокли. Förstoring av Kikare. Potencia óptica de Prismáticos. Ingrandimento del Binocolo. |
Most binoculars use a standardized nomenclature to denote power, such as “6x15”. This designates the power and the objective lens diameter in millimeters. So “6x15” is six power using a 15mm objective lens diameter. The power is the magnification, and the larger the number then the greater the magnification. The objective lens is the last lens on the binocular furthest from the eyepiece. Size of this affects the light gathering ability of the binocular, and is also used in designing the field of view of the binocular. |
Objective lens diameter |
Field of View of Binoculars. Sichtfeld Fernglässer. Champ de Vision des Jumelles. Поле зрения бинокль. Synfält Kikare. Campo de Visión Prismáticos. Campo di Vista del Binocolo. |