In this era, it's extremely difficult to expand ports by manpower; places that can become major harbors, capable of hosting and anchoring large numbers of ships, are all heaven-sent, naturally sheltered from the wind. Moreover, the local terrain needs gently sloping tidal flats, solid seabeds, and no abundance of reefs or hidden rocks nearby, only then can ships come and go conveniently, and docks, piers, warehouses and other basic facilities be built.
Such terrain is one in a hundred; for example, in Ise Bay, there are only two such spots, and in the Izu Sea Area, only Shimoda Port truly counts as a natural and excellent harbor.
Here the coastline curves inward as a whole, forming a semi-circular bay. Shimoda Port sits at the apex of that semi-circular arc. Before the Satomi Navy appeared, almost all Wanjin merchant ships had already entered this bay, waiting in line at the dock and the piers to unload cargo.
