Nara holds one of the wettest corners of Japan, and that is why everything else fits into the dry corner

Almost everyone arrives in Nara for the same reason and with the same image in mind: a flat park with deer and wooden buildings, forty minutes by train from Kyoto or Osaka. That image is accurate and tiny. It corresponds to one corner of a prefecture most of which looks nothing like it.

The rest is mountain, and at its southern end sit some of the wettest places in all of Japan. That asymmetry explains why the country's history began precisely in the top left-hand corner.

01 A prefecture without a sea

In an archipelago where almost everything is within sight of water, Nara is one of eight prefectures with no coast. It is wedged into the centre of the Kii Peninsula, surrounded by Osaka, Kyoto, Mie and Wakayama, and its relationship with the sea has always had to cross a mountain.

That fact, which looks administrative, is what orders everything else. Without a port there is no direct maritime trade, and without maritime trade the big city ends up going elsewhere. But before that, the lack of coast was precisely an advantage.

02 Five thousand millimetres in the south

Sixty per cent of the prefecture is the Kii Mountains, and there something happens that hardly anyone associates with Nara. Annual accumulated rainfall runs from 3,000 to 5,000 millimetres, among the highest figures in the country. For scale: that is three to five times what falls on Madrid, and more than double what falls on the city of Nara itself.

The mechanism is textbook. Humid air arriving from the Pacific runs head-on into a mountain massif, is forced to climb, cools and unloads. All of that happens on the southern flank, and whatever continues north arrives already wrung out.

The result is permanent wet forest, moss covering the rock and deeply cut ravines. It is a landscape far closer to what you expect of temperate rainforest than to the idea of Japan people take away from Kyoto.

03 The habitable 23%

The demographic consequence sits in an official figure: of the prefecture's 3,691 square kilometres, only 851 are classed as habitable. That is 23%, placing Nara 43rd of 47 prefectures by usable area. Everything else is slope, forest or ravine.

And that 23% is not spread out: it is concentrated almost entirely in the northwest, in the Nara Basin, a plain closed by mountains on every side. Practically the whole population of the prefecture lives there, and everything a visitor identifies with the name is there.

04 Why the capital was put here

In the year 710 Japan's first permanent capital was established in that basin, and it stayed until 784. With the physical map in front of you, the choice is anything but arbitrary.

A capital of regular layout needs extensive flat ground, and this basin is the only one in the area that offers it. It needs shelter, and the mountains close it on all sides. It needs enough water but not too much, and at 1,365 millimetres a year the city of Nara is far from both drought and the south's 5,000.

Put another way: nobody chose a beautiful place. They chose the only rectangle of flat, dry, protected ground available, and drew the city on top of it.

05 And why it left

Seventy-four years later the capital moved, and the same geography that had made it possible largely explains why. A closed basin is an excellent place to settle and a mediocre one to grow: no port, no great navigable river, and everything that comes in or goes out has to cross a range.

The cities that replaced it are all better connected to water. And that relative abandonment had a fortunate consequence for today's traveller: the basin stopped rebuilding on top of itself. Where other capitals have been raised and demolished twenty times over, here much of the old ground ended up beneath farmland.

06 What this changes for the traveller

The first consequence is about scale. What almost everyone calls Nara is a park of a few square kilometres on the edge of a basin occupying 23% of a prefecture whose other 77% is mountain. Mistaking the part for the whole is especially easy here.

The second is that the south exists and is within reach. From the city centre to the start of the Kii Mountains is a long hour by train or car, and the change of landscape is total: from urban plain to wet forest and ravines. It is one of the fastest and least travelled transitions in Japan.

The third is about mental packing. If you go south in summer or autumn, expect real rain rather than a shower: five thousand millimetres a year do not fall discreetly. That the city is dry says nothing about what happens sixty kilometres further down.