Kochi

This is the most heavily wooded prefecture in the country, the catchments are largely undammed, and the rivers run clear and rise fast. The low concrete crossings you will see spanning them have no parapets and no sides at all, which looks like an oversight and is the opposite of one: they are designed to be submerged when the river comes up, so that floodwater and debris pass over the deck instead of piling against a barrier and taking the whole structure out.

Driving or walking one is a strange sensation and one of the most memorable things here. Treat them with respect — they are narrow, there is nothing to stop you going off the edge, and they are genuinely closed and impassable when the water is high. After heavy rain, check before setting out rather than arriving to find out.

Three days, because Kochi is long, thin and mountainous, and the good things are spread along a coast that takes hours to drive. The city has a surviving original castle and the best Sunday market in Japan, running the length of a street since the seventeenth century.

The two capes are the other draw and they are a long way apart: Muroto to the east is about two and a half hours from the city, Ashizuri to the south-west more than three. The Shimanto river, often called the last clear river in Japan, runs through the west with low submersible bridges crossing it.

Three days does the city and one direction. Five does the city, the river and both capes. Two days is the city and a river or a cape, and that is a legitimate short trip — but do not attempt both capes in under four days.

A car, almost without qualification. Kochi is the least densely served prefecture on Shikoku: one railway along part of the coast, buses that run a few times a day, and capes at the end of long peninsulas. The Shimanto river's bridges and the coastal roads are driving destinations in the literal sense.

Kochi City itself is walkable with a tram, and the castle and the market are both central, so a day there needs nothing. Everything beyond it does. Note that this is a Pacific-facing prefecture with genuinely heavy rainfall — the interior mountains record some of the highest totals in the country — and mountain roads here are narrow and prone to closure.

A market has been setting up along the road toward the castle on Sunday mornings for some three hundred years, and it is still a working one: produce, plants, tools, knives, prepared food, and stalls run by people who grew or made what is on them. It stretches for the better part of a kilometre and it is the single best hour in the city.

The scheduling implication is blunt. If your itinerary puts you here from Monday to Saturday you will not see it at all, and there is no substitute. Work the day of the week into the plan before you book anything, arrive in the morning rather than at midday, and eat there instead of beforehand. It is also the easiest place in the prefecture to talk to people, which is not true of the castle or the museums.

Late summer and early autumn. Kochi takes the full force of Pacific typhoons and its rainfall totals are among the highest in Japan; roads close, the rivers rise fast, and a coastal itinerary can simply become impossible for a few days.

The Yosakoi dance festival in August fills the city. Winter is mild on the coast — this is one of the warmer parts of Honshu and Shikoku — and is a genuinely underrated season for the drive. Spring is the best of it, with the river at its clearest and the coastal roads at their most pleasant.

Kochi Airport is about 40 minutes from the city and the fastest way in, roughly an hour and a quarter from Haneda. By rail, the Nanpu limited express runs from Okayama in about two and a half hours after the shinkansen. Once here, distances are the problem: the prefecture is long, and Cape Ashizuri at the western end is over three hours from the city by train and bus, while Cape Muroto to the east has no railway at all. The Tosa Kuroshio Railway extends the network partway. For the Shimanto valley, the capes and the mountain villages, a car is effectively required.

Kochi is one of the wettest places in Japan and takes the brunt of the typhoon season from August into September, when travel plans should stay flexible. It is also one of the sunniest between storms. Winters are mild with January highs near 12°C and no snow on the coast. Summers are hot above 33°C. The Yosakoi festival fills the city on August 9–12. The Shimanto is best from late spring to early autumn for canoeing and swimming, and bonito is landed most heavily in spring and again in autumn. The Sunday market runs every week of the year.

Katsuo no tataki is bonito seared hard over burning rice straw so the skin chars while the centre stays raw, then sliced thick and eaten with garlic and salt rather than soy — the straw is the part that matters, and the harbour at Kure is where to watch it done. Sawachi is a large communal platter of sashimi, sushi and fried food, built for drinking parties. Kochi drinks more than most of Japan and has the local breweries to match. Yuzu is grown in the mountain villages and turns up in everything from ponzu to salt.

A first visit is the city and the Sunday market, and the market is not a garnish. It runs for about a kilometre down the street toward the castle, it has been happening weekly for three hundred years, and it sells vegetables, knives, plants and cooked food to residents rather than to visitors. Add the castle, which is one of the twelve surviving originals and has its main gate and keep both intact, and eat seared bonito.

A second visit takes a car west to the Shimanto river and the Ashizuri cape. The river's low bridges without railings, built to be submerged rather than swept away in a flood, are the image of rural Shikoku, and the coast beyond is empty in a way little of Japan manages. It is a long drive and that is the point.