Birmingham physically interposed itself between the merchantman and three Japanese cruisers positioned on the seaward route out of the harbor. Folkestone moved farther inside, where her shallower draft could be valuable if the water proved too restricted for a cruiser. A sloop was a calibrated choice because it showed that Britain was serious without sending a second cruiser that could look like deliberate escalation. Japan's reaction to so modest a reinforcement became a test of its intentions as well as another layer of protection.
Notable Point · 35:57-38:58
How a sloop sharpened the diplomatic signal
Birmingham placed itself between the merchantman and Japanese cruisers, while Folkestone's shallow draft and modest profile made a second British ship a pointed but less provocative signal.