hiking the Kumano Kodo Nakahechi imperial route

The Kumano Kodo is a network of paths of pilgrimage towards places seen as sacred by either buddhists or shintoists (or syncretists!) from the 700’s. Meaning for non-believers a well-established system of ancient hiking paths in the mountainous forests of the Kii peninsula, south of Osaka, Kyoto and Nara. Apart from the potential dangers of heavy rain, like massive mudslides, there is no particular difficulty in the hikes (which were done wearing braided straw shoes, the waraji sandals) and a dense network of guest-houses and bus routes makes it possible to adapt the length of the day trips to one’s speed. While this is the place of Japan with the maximum of rain, the hot temperatures actually make it more than bearable when it is a shower and not a typhoon!day one

14km, from Takijiri-oji to Chikatsuyu-Oui, 7:30 hours, 1100 positive gain, nice trail all the way, maximum temperature 32°, met two dozen hikers and two trail runners, got tired by the end, confused one minshuku guest house for another, the hosts of the first one drove us to the second and later brought me back my sandals I have left in their car, no English speaking at the second place and no Onsen but very nice bento box and a pleasant conversation with a couple of Ausso-Danish young women spending a month in Japan and four on the trail. Entire path under cover, making high heat so much more bearable! Not too much in terms of views despite following ridges and visiting tops. Plenty of huge butterflies.

day two

6km, from Doguyaba-bashi (reached by bus) back to Tsugizakura, 2:30-3:00 hours, maximum temperature 30⁰, mixed trail and road, rain spells and showers, met three other couples of hikers, arrived too early at the guest house, waited in a one-room thatched traditional tea house by the side of the road with free hōji-cha tea offered by a very nice old man (not English speaking, alas, which limited the exchanges), reached the guest house at the same time as a Canadian-Spanish couple embarked on a massive six month travel. The dinner was imperial with a whooping ten dishes, all delicate and beautiful. Plus getting our names in Japanese Kanji characters.

day three

9km, from Doguyaba-bashi (the host gave us a ride) to Hosshinmon-oji, 4 hours, 600 positive gain, maximum temperature 29⁰, heavier rain spells, first part really nice then switching to forest track due to closures, finishing detour on tar road, took the infrequent bus to Yunomine-Onsen due to the closure. A few more couples and lone hikers passed us. Stayed at a larger guest-house minshuku with its own natural onsen plus normally access to the river with swimming waterholes. Far from Hongu and Yunomine, alas. But also welcome place to wait two days for the typhoon Krosa to pass by Western Japan.

day four

14km, from Nachisan to Koguchi, 930 positive gain and 1260 negative gain!, alas cancelled as advised by local tourist office due to uncertainties on the state of the trail, took the bus instead and enjoyed a swim after a very hot day in the now quiet Kumanogawachonichi, next to a most congenial guesthouse. Very quiet place, superlative food!

day five

13km, from Koguchi to Ukegawa,  690 positive gain, 5:30 hours, maximal temperature 29⁰, sunny, very enjoyable part of the trail with many ridge walks, no road share, hardly any trace of the typhoon, and early arrival in Hongu. Met with a guest from the Yunomine-Onsen guest house hiking the other way. And very few others.

golden glory [jatp]

Nara snapshot [jatp]

Kudzu [クズ] delicacies [jatp]

a problem that did not need ABC in the end

While in Denver, at JSM, I came across [across validated!] this primarily challenging problem of finding the posterior of the 10³ long probability vector of a Multinomial M(10⁶,p) when only observing the range of a realisation of M(10⁶,p). This sounded challenging because the distribution of the pair (min,max) is not available in closed form. (Although this allowed me to find a paper on the topic by the late Shanti Gupta, who was chair at Purdue University when I visited 32 years ago…) This seemed to call for ABC (especially since I was about to give an introductory lecture on the topic!, law of the hammer…), but the simulation of datasets compatible with the extreme values of both minimum and maximum, m=80 and M=12000, proved difficult when using a uniform Dirichlet prior on the probability vector, since these extremes called for both small and large values of the probabilities. However, I later realised that the problem could be brought down to a Multinomial with only three categories and the observation (m,M,n-m-M), leading to an obvious Dirichlet posterior and a predictive for the remaining 10³-2 realisations.

off to Osaka

Today, I am off to Japan to visit Kengo Kamatani at Osaka University (where I will give a seminar on Tuesday) for a week and then for two weeks of vacation hiking the Kumano Kodō, a network of ancient pilgrimage routes in the Kii peninsula, south of Osaka. (Presumably with little access to the Internet or even to my laptop!)

Denver snapshot [jatp]