The cover of my grandfather's photo album creaks when you open it, like an arthritic joint, worn after 70 years of reminiscing. Inside, behind a veil of tissue paper, are carefully mounted images of saw-toothed peaks and yawning valleys in the Japanese Alps; and my grandfather, slumped in a rickety wooden chair, arms hanging over the back.
I can read something in his eyes, in his posture, in the grin of satisfaction and fatigue that creases his face from ear to ear. Something tells me this moment, captured on celluloid between the open and close of the shutter, was among the best in his life.
It was 1936 and Japan had just opened its doors to foreign trade and foreign companies. My grandfather was on a four-year secondment for New Zealand Insurance in Tokyo, and on his time off, would go hiking in the hinterland with mates.
The album records an epic six-day traverse across the peaks surrounding Kamikochi valley, deep in the mountainous interior of Nagano Prefecture.
Seventy years on, almost to the day, I follow a well-worn trail along a river bank shaded by cypresses, Japanese maples and ornamental pines. The Azusagawa River cascades over granite boulders to my left like a long marble staircase twisting up the Kamikochi valley.
There's a sweet scent of cedar in the air and the Myojin peaks rise steep and buttressed from the opposite bank; wooded flanks striated by couloirs of snow and freckled with moraine; as timeless as the photos in the album.
This is a pilgrimage of sorts; to walk up a valley and back in time through a landscape of photographs; to remember my granddad, and by following his route, perhaps get to know him better.
Last night I was in a sorry state, sweating and panting and dragging my backpack through the tunnels and turnstiles of the world's busiest train station. All 3.2 million commuters in Shinjuku seemed to be headed in the opposite direction.
I was engaged in frantic and exhausting pantomimes involving much arm-waving and a peculiar dialect of English I employ in the hope it sounds more like Japanese all just to figure out where the bus stop was.
The writhing technopolis of Tokyo must be unrecognisable from my grandfather's day, but Kamikochi's landscape remains untouched by modernity, frozen in time by isolation, and enshrined in environmental legislation.
I walk for four hours beside the river, until the valley splits in two, then three, and the river narrows to a raging tributary rushing over car-sized monoliths of granite. The melt-water is so cold it feels like I'm standing on broken glass.
Precipitous valley walls tower over me, scoured by glaciers and eons of fluvial erosion, and rimmed with mountains folded and creased into pinnacles. Forests cling to granite cliffs and the diminutive tracks are punctuated by rock slides and avalanches of snow 30m across.
And yet the daintiest wildflowers grow on the riverbanks, butterflies sparkle in the forest and the trees are decorated with mosses like baroque filigree. Kamikochi is a place of truly sublime, awe-inspiring beauty.
Ahead is the sheer-sided peak of Yari-ga-take, tangled with ice and cleaving the clouds like a knife. My grandfather stood at the top 70 years ago, but this year the route is inaccessible; blocked by snow and ramparts of blue ice; the frozen legacy of an unseasonably harsh winter.
I gaze at Japan's Matterhorn from a distance, as a slow tide of disappointment begins to lap at my sentimental plans. The route is impossible for all but the Hillarys of this world, and regrettably I am not in their company, not today at least.
After a little tree-kicking I reluctantly settle for retracing the part of the route still possible; the last long hoop from Jonen to Kamikochi. I'll try to imagine what the rest must have been like, peering back through history's smoky window.
I shuffle back to Yoko-o Hut where a sallow lady charges me Y9000 ($130) for a miniature bunk and a rag. The rag is to be used for bathing under frigid water in the sink of a unisex loo, which wouldn't normally irk me much, but the toilet seats are heated, and the cruel idiosyncrasy makes the experience all the more unpleasant.
On the upside, my salubrious accommodations include dinner: miso soup, a piece of nondescript fish and a cup of grated something the consistency of mucus. The soup is fine.
The next day, after another refreshing cup-o'slime, I make for the hills to intersect my grandfather's route 1200m above me. The thin orange line on my map crosses the isolines with alarming frequency. In walking terms, this translates into a never-ending incline of punishing gradient.
I struggle through wet forest and drifts of snow half a metre deep that collapse unpredictably beneath my weight. It's a silly lottery that starts out funny and gets rapidly less amusing as snow fills my boots and penetrates my pants.
A cold wind rattles in the canopy and the valley replies with the rumbles of rock falls and crashing trees like the stirring of a slumbering beast.
After a couple of hours in the clammy forest I climb above the tree line and wander through low brush on to a shale ridge in thick cloud.
A typhoon in the south of Japan is driving heavy rain up the coast and dumping it unceremoniously on my head. A wicked wind increases rapidly and my jacket crackles like gunfire. The route to Jonen continues along an exposed ridge for four hours through 2.8km, but given the deteriorating conditions I run for my life to Choga-take, a climbing hut half an hour away.
It's an immaculate shelter with roaring kerosene burners, dark timberwork and a lingering scent of nostalgia. It's not hard to imagine my grandfather huddled over one of these burners. But then again, he never had to huddle over anything. He wasn't doused by a typhoon or up to his knees in snow; the blighter had near-perfect weather and he probably paid less for the hut as well.
And suddenly my disappointment turns into a ridiculous sense of injustice. The guide books should read: Best time to visit: Summer 1936; when it never rains, the tracks are open, accommodation is cheap and the huts still serve filet mignon to foreigners.
Somewhat refreshed by the thought I'm so hard-done-by, I strip off the rain-soaked jacket, don the requisite slippers and stride into the hut.
But the abject horror on the face of the hut warden stops me in my tracks and signals one of those all-too-familiar breaches of Japanese footwear etiquette. The slippers I'm wearing (I'm instructed in no uncertain terms) are to traverse the 2m of concrete to where an alternative pair, for use on wooden floors, are waiting.
The sight of me, standing on a wooden floor in slippers so very clearly reserved specifically for use on concrete, nearly brings the poor guy to tears. The trouble is, the cherry-red plastic slippers only cover my fat foreign toes, and my heels hang over the back. No amount of toe-scrunching or heel-dragging will help; the plastic is absolutely frictionless, like walking on Teflon.
The solution of course is to waddle, knees bent, balancing as if on a tight-rope; like a transvestite wearing stilettos for the first time. Embarrassingly, one falls off and tumbles down the stairs in front of the assembled hikers as I hop after it on one unstable slipper. Heaven only knows how the Japanese manage with such aplomb.
I thank the warden for the heads-up, botching the familiar "domo arigato", and instead I offer "domo oregano"; loosely translated, thanks for the herbs. Humiliation is complete.
When my grandfather was here, Japan occupied Korea and was primed for a bloody invasion of mainland China. The next 15 years would be the most turbulent and destructive in the history of the Japanese nation.
My grandfather went on to a post in India where he contracted tuberculosis and returned to New Zealand as war broke out in Europe. He was bed-ridden for months as TB stole mobility from his hip, crippling him with a limp that lasted the rest of his life. He spent the time creating albums from his photographs overseas, meticulously labelling each image; a process which enabled me to retrace his route today.
Unable to go to war he watched from his bed as Japan invaded Guam, Wake, Midway and the Philippines. They sacked the Netherlands East Indies (now Indonesia), the entire Malay peninsula and the British forces of Singapore, Burma and islands as far south as the Solomons. Victory after victory, then one catastrophic defeat.
How torn he must have felt when the atomic bombs dropped on Hiroshima and Nagasaki.
His four-year secondment and this hike - probably the last long walk of his life - were all in the company of Japanese. These, the strange twists of fate that are the fabric of human existence, and the cataclysmic trajectory of nations.
If only he could see Japan now. How different it would seem in parts; and here, how much the same.
A ferocious wind rattles the roof of the hut all night, threatening to peel it off and devour us all. But by morning it has gone and in its place, snow falls silently. Cloud hangs thick in the air, absorbing all sound and I am swallowed by the murk. I mark bearings on my map and follow the swinging needle of my compass through the fog, down the icy ridge, around frozen lakes and into the dank forest again, bound for Kamikochi.
The Japanese belief system is based on the transience of life, delicate in its passing. Theirs is a world of impermanence, a world of constant change. Like the fleeting departure of cherry blossoms; life, like all things, will pass.
My grandfather is gone now, but these mountains remain, defiant of change, memorials to an ancient Japan, silent witnesses to years of turmoil, and for me, in some strange way, 3000m-high cenotaphs to a granddad I wish I'd known in his youth.
Getting there: Japan Airlines and Air New Zealand offer direct flights to Tokyo.
Getting around: When visiting Japan, the best way to get around is by train; but be sure to buy a one-week or two-week Japan Rail (JR) pass before you leave. It allows unlimited travel on JR trains including the blistering fast Shinkansen for a fraction of the regular ticket price available in Japan. It can only be bought outside of Japan. JR Rail Passes are available from JALPAK in Auckland, phone (09) 3032887
Kamikochi can be reached by train from Tokyo to Shinshimashima, then by bus to Kamikochi. Alternatively take the hard-to-find and slightly uncomfortable overnight bus from Shinjuku Station to Kamikochi direct.
Huts can be booked through the Kamikochi Visitors Centre (+81 263 952606) and cost around Y9000/night.
Further information: The best information, track notes and maps are available in Lonely Planet's guide to hiking in Japan.
For general information on Japan see jnto.go.jp.
Best time to visit: Summer 1936!