Just giving my little contribution to this thread
![Wink ;) ;)](styles/default/xenforo/smilies/xwink.png.pagespeed.ic.j4HKyMA3Vq.png)
A caliber 89 from the late 50s/early 60s in platinum.
According to my research the case is made by a Japanese company called isomura. In the 1960s they were the Japanese distributor for IWC watches, produced a small number of platinum cases for the Japanese domestic market. These cases were made in Japan in order to avoid the prohibitively high tariffs on importing platinum cases from Switzerland.
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