Oku-no-yama

Oku-no-yama is a Kyoto tea cultivar registered under Japan’s Plant Variety Protection Act in 2002, propagated by cuttings from a single, very old zairai (landrace, seed-grown) tea tree in the Okunoyama garden in Uji. It is not a bred cultivar in the usual sense of a research station’s controlled cross: it is one plant, fixed by cloning, chosen from a population of zairai trees that had never been catalogued at all. Against Yabukita it is a later-budding plant with an elliptical mature leaf and, per its own registration record, more numerous shoots at picking than the Uji standard Asahi - officially documented traits used to establish that it is legally distinct from both. It is processed almost entirely as tencha and milled to matcha, with a small gyokuro line also produced, and it exists nowhere outside the one garden it is named for.

Lineage

• Uji zairai (landrace) seedling, Okunoyama garden - an unnamed, seed-grown individual from the garden’s standing population of native tea trees, propagated onward by cuttings from a single mother plant that Horii Shichimeien states is more than 400 years old.

Oku-no-yama has no controlled cross behind it and, strictly, no named parent: MAFF’s own registration record describes it as bred “by selection from among Uji zairai” (宇治在来種の中 から選抜をして育成), the same wording used for its sibling Narino. The two were registered on the same day under sequential numbers - Narino as registered variety No. 10751 (application No. 12426), Oku-no-yama as No. 10752 (application No. 12427) - both filed by Horii Nobuo on 13 March 2000, which is about as close to documentary proof of a shared origin as a pair of zairai selections is likely to get. They are not clones of each other, though: Horii Shichimeien’s own account describes a roughly 20-year screening of the garden’s zairai population (from 1980, or 1981 in its longer telling) that yielded two distinct plants worth keeping, of which Oku-no-yama was judged the deeper green and more gyokuro-like, and Narino the higher in theanine. No cultivar bred forward from Oku-no-yama is documented in any source consulted for this record.

History

The garden behind the name

Okunoyama is one of the historic Uji Seven Tea Gardens (宇治七茗園 / 七名園), the plantings tradition credits to Ōuchi Yoshihiro, acting on the order of the shogun Ashikaga Yoshimitsu, and whose existence is first documented in the 1564 text Bunrui Sōjinmoku. Horii Shichimeien’s own company name - 堀井七茗園, “Horii of the Seven Tea Gardens” - refers directly to this tradition. A 2019 radiocarbon-dating study of the Okunoyama garden’s soil profile (Inoue et al., Japanese Journal of Soil Science and Plant Nutrition) found phytolith and carbon evidence for shaded cultivation (覆下栽培) there from at least the early fifteenth century - roughly 1400-1440 by the paper’s calibrated dates - about 150 years earlier than the practice had previously been documented at Uji, and independently consistent with Horii Shichimeien’s own claim that the garden has been under continuous cultivation for close to 600 years. The paper describes Okunoyama as the sole one of the historic seven gardens still in production today. Horii Shichimeien states it took over the garden in the middle of the Meiji era (roughly the 1880s-90s).

Selection and registration

Between 1980 and 2000, Horii Nobuo (堀井信夫), the family’s fifth-generation head, worked through the garden’s zairai population looking for individual plants worth preserving as named cultivars, rather than left as an anonymous mixed stand. Chapter 4 of the company’s own 7 Stories describes the funnel: roughly 2,000 trees narrowed over several years to 58, then 24, then 8, with the final two chosen in 1994 and grown on trial until registration. Those two were Narino and Oku-no-yama. Of the latter, Horii is quoted as saying “there are no leaves this deep green - it’s dyed just like natural gyokuro,” and Horii Shichimeien credits that depth of colour as what secured the registration - though MAFF’s own record rests the plant’s legal distinctness on mature-leaf shape, budding time and shoot number rather than on colour. Only one mother tree

• reportedly over 400 years old - stands in the garden today; every Oku-no-yama plant is a cutting-propagated descendant of it.

An application for registration under the Plant Variety Protection Act (種苗法) was filed on 13 March 2000 (application No. 12427) and published on 20 October 2000. The variety was formally registered on 14 November 2002 as registered variety No. 10752, with Horii Nobuo named as both applicant and breeder, his address on file as 84 Uji-Myōraku, Uji City, Kyoto (611-0021). This is a Plant Variety Protection Act registration, not a MAFF Cha Norin (茶農林) number, and not a Kyoto prefectural recommended cultivar: neither the Kyoto Tea Trade Association’s cultivar page nor the prefectural tea research institute’s own list Oku-no-yama among Kyoto’s recommended cultivars, which currently number twelve (Hoshun, Ujimidori, Kyomidori, Asahi, Yabukita, Ujihikari, Tenmyo, Samidori, Oguramidori, Gokou, Komakage and Okumidori). The registration record also states a 25-year statutory term for the breeder’s right, but records that right as having lapsed on 15 November 2011 - nine years in, not twenty-five. No source found explains the discrepancy; a lapse of this kind more commonly reflects non-renewal of an annual maintenance fee than the full term running its course, but that reason is not stated in the record and should not be assumed.

Today

Horii Shichimeien processes the whole of each year’s Oku-no-yama harvest as tencha and mills it into matcha under the name “Okunoyama”. A separate gyokuro line is also produced, rolled to order by a tea-rolling specialist in Uji-Shirakawa; it won first prize in the gyokuro category at the 2019 (Reiwa 1) Uji City Tea Competition. Both remain single-garden, low-volume products sold directly by Horii Shichimeien rather than cultivated more widely.

Characteristics

Oku-no-yama is a late cultivar. Its own registration record rates budding (ほう芽期) 晩 (late) and picking (摘採期) やや晩 (somewhat late), and gives later budding as a point of difference from both Yabukita and Asahi - the two comparison cultivars MAFF used to establish its legal distinctness - though no source found quantifies the gap in days. A separate cultivar reference (日本茶備忘録) independently classifies it as 晩生 (late-budding) and a gyokuro cultivar, consistent with the registration record.

The registration’s plant description gives a fuller picture than is normal for so obscure a cultivar. Growth habit is slightly upright with strong vigour and a large stool spread; leaf layer thickness is medium. At picking time the shoots are numerous and fairly uniform in development. New leaves are somewhat elliptical, medium in size and thickness, deep green, and notably glossy; mature leaves are elliptical, deep green, with a heavily wrinkled surface and somewhat wavy margins. Branching is somewhat frequent, with somewhat short internodes and a fairly steep leaf-attachment angle. Against Yabukita it is distinguished chiefly by that elliptical mature-leaf shape and its later budding; against Asahi, by more numerous shoots at picking time and, again, later budding.

The cup follows the leaf: a deep, even green when milled, which Horii Shichimeien frames explicitly against gyokuro rather than sencha or ordinary tencha - “dyed just like natural gyokuro,” in Horii Nobuo’s own description. The registration record itself rates finished-product appearance, aroma, liquor colour and flavour all above average, and Horii’s own tasting notes describe a mild, unforced umami rather than an assertive one. The gyokuro version is described as elegant, with a pronounced 覆い香 (ooika, the “covering aroma” characteristic of well-shaded tea).

As with Narino, there is no multi-region agronomic trial data for Oku-no-yama - no published yield in kg/10a, no disease-resistance rating - because it has never been grown outside the one garden it was selected in. What does exist, unusually for a cultivar this obscure, is the detailed morphological description filed with its own Plant Variety Protection Act registration, which is the basis for most of the characteristics recorded above.