Hokkaido

Hokkaido is Japan's northernmost main island, and its southern coast at the Tsugaru Strait sits at the boundary between the Pacific Ocean to the east and the Sea of Japan to the west. The strait itself, roughly 20 km wide at its narrowest between Cape Shirakami on the Hokkaido side and Cape Tappi on Honshu, is both a navigation corridor for the Seikan tunnel railway beneath it and a zone of meaningful tidal current. The tidal regime along the southern Hokkaido coast is semidiurnal, with two roughly equal highs and two roughly equal lows per day; mean range in the Hakodate area runs approximately 1.2 to 1.5 m, making it a moderate microtidal-to-mesotidal coast. The Tsugaru Strait connects the Pacific and the Sea of Japan, which have slightly different tidal phases and amplitudes, and the resulting through-flow creates tidal currents that matter to vessel navigation and to the squid-fishing fleet that works the strait at night. Hakodate sits on a narrow isthmus at the southern tip of the Oshima Peninsula, with the city flanked by Hakodate Bay to the west and the open Pacific approach to the east. The port has served as one of Japan's oldest treaty ports — opened to foreign trade in 1859 — and the waterfront retains that history in its brick warehouses along the Motomachi district, now restaurants and shops looking back across the bay. The morning market adjacent to the station, open from roughly 5 am, operates on the rhythm of overnight fishing returns from the strait rather than any direct tide reference, but the squid catches landed there are caught by vessels reading the tidal currents closely. The Japan Coast Guard and Japan Meteorological Agency maintain the official tide predictions for Hakodate. Open-Meteo Marine drives the gridded predictions on TideTurtle pages for this region, pulling from the broader Pacific and Sea of Japan model grid that covers the Tsugaru Strait approach.