Daiichi Kikō
Daiichi Kikō K.K. (第一機工株式会社) was a Japanese camera maker. During the war, it made the Primo 4.5×6 folders, distributed by Ōsawa Shōkai (大澤商會), who later distributed the Primoflex and Primo Junior TLRs. Its logo is DK mixed together inside a circle[1].
The company is probably unrelated to the later Daiichi Kōgaku.
