For years I’ve owned a Japanese naval artillery shell fuze and not a clue as to its intended use. Recently I googled around the web and found on a web site called Inert-Ord pictures of a fuze very similar in appearance to my own. The fuze pictured there is called a “type 91 naval anti-aircraft mechanical time fuze.” With a couple of exceptions it’s very much like mine. There is a potential catch in that the pictured fuze has no dimensions given, nor is there anything in the pics to suggest scale.
I can say my fuze is 76 m/m in length, maximum width is 58 m/m and diameter over the threads at bottom 47.5 m/m. Fuze is mostly nickelled brass, with an aluminum cap. Markings consist of the Toyokawa Naval Arsenal mark, an anchor and (90 degrees around the fuze) the kana character “se” and the capital Latin lettes D K R. Assuming mine and the pictured fuzes are variants of a basic type I seem to have a fuze for the 12.7 cm./40 type 89 naval AA gun. The fuze pictured in the site mentioned above has what is described as “a gear ring for automatic time settings.” My fuze lacks that feature. Comments most welcome. Jack