When an automated voice on the Hanzomon subway line advises you to change to JR Sobu line at Mitsukoshi-mae, keep in mind that while Mitsukoshi-mae and Shin-Nihonbashi stations are be in fact connected by a network of tunnels, and even Wikipedia lists it as a transfer point, it is quite a trip and cannot be too much different from leaving the subway at a random location in Tokyo and walking to the next JR station from there. Stay on until Kinshicho and change there.