Originally Posted by T-Mar

I've seen this brake several times but have been unable to determine the brand. While Yoshikawa is a definite possibility, so is Buffalo/Cherry and about a half dozen other, lower tier, Japanese brands that were favoured by marketing brands due to their lower pricing.

As for the bicycle itself, this particular version of the Lark rear derailleur suggests circa 1969-1971. The frame serial number may also provide some insight.