Tenmyo

Tenmyo is a mid-season Japanese tea cultivar bred at the Kyoto Prefectural Tea Research Institute, selected in 1977 from open-pollinated seedlings of Samidori and registered in 2006. Unlike most of Kyoto’s showcase tencha cultivars, which are grown and hand-picked in small, intensive plots, Tenmyo was bred explicitly for mechanical harvesting: the institute’s stated aim was a cultivar that could lift the quality of machine-picked tencha, a role Yabukita had mostly been left to fill by default. It buds within a day or two of Yabukita, takes shading colour and aroma well, and is processed into tencha, matcha and, to a lesser extent, gyokuro.

Lineage

• Samidori (さみどり) — the seed parent. Samidori is itself an unregistered but foundational Uji cultivar, selected from landrace tea bushes by Koyama Masajiro and used at the Kyoto institute as a base population for further selection. Tenmyo is one of the natural hybrid seedlings grown from its open-pollinated seed.
• Pollen parent — unrecorded. Because the seedling arose from open pollination in a mixed planting rather than a controlled cross, the male parent was never identified and cannot be recovered now.

This is a single-plant selection from an open-pollinated seedling population, not a controlled cross: Tenmyo’s breeders chose the best individual out of many Samidori-seed seedlings rather than deliberately combining two named parents. Its true sibling is Houshun — strain “53-7” against Tenmyo’s “53-38” — selected from the same 1977 batch of Samidori seedlings at the same institute and registered in the same year. The two diverged sharply from there: Houshun was carried forward as an ultra-early gyokuro cultivar, while Tenmyo was developed as a medium-season, machine-harvestable tencha cultivar. No further descendants of Tenmyo are documented in the sources consulted.

History

The Kyoto Prefectural Tea Research Institute breeds original Uji cultivars by two routes: selecting single plants out of Uji zairai (landrace) stands collected from around the prefecture, and crossbreeding using existing Uji cultivars as seed parents. Tenmyo and Houshun both came from a third, intermediate route — open-pollinated seedlings grown from Samidori seed, from which the institute began selecting promising individuals in 1977 (Showa 52). Tenmyo carried the working strain name “53-38” through the trial period.

The two cultivars were registered together on 14 December 2006 (Heisei 18) — Tenmyo as Plant Variety Protection registration No. 14535, Houshun as No. 14534 — and announced jointly by the institute under the title “About the new cultivars Houshun and Tenmyo”. The institute framed Houshun as an ultra-early gyokuro cultivar and Tenmyo as a “high-quality, high-yield tencha cultivar” (良質・多収てん茶用品種), noting three points in Tenmyo’s favour: strong vigour and good stock spread; upright new shoots that suit mechanical picking; and bright-green leaf that readily takes on a good shading aroma. The institute’s own framing was pointed about the purpose: for machine-harvested tencha specifically, Tenmyo was expected to bring a substantial quality improvement over Yabukita, which growers had been using for that role largely for lack of a better-suited alternative. Kyoto’s Uji Tea Trade Association’s subsequent cultivar guide still describes Asahi, Samidori and Ujihikari as the prefecture’s primary hand-picked tencha cultivars, with Tenmyo positioned separately as the institute’s answer to the growing share of tencha picked by machine.

The Uji Tea Trade Association’s English-language cultivar page glosses Tenmyo’s name simply as “Exhibition” — evidently a literal rendering of 展 (“to display”) and 茗 (“tea”) rather than a romanisation — but no source found explains why the characters were chosen.

Characteristics

Tenmyo is a medium-season cultivar: its budding and picking period runs, like Samidori’s, one to two days later than Yabukita. That places it close to the middle of the calendar this collection uses, and a long way from Houshun’s ultra-early budding despite the two having been selected from the same seedling population in the same year — a reminder that budding time is not conserved even between siblings drawn from one open-pollinated batch.

The bush carries strong vigour and a good, broad stock spread, similar to or exceeding Samidori. Its new shoots grow upright, the trait the institute bred it for, since an upright flush is what allows a mechanical harvester to take a clean, even pick. New and mature leaves are oval, and both larger and thinner than Samidori’s. First-flush yield is high and on a par with Samidori, but the yield is carried differently: Tenmyo is a bud-weight type (heavier individual buds), where its sibling Houshun is a bud-number type (more buds per unit area).

Processing quality is reported as roughly equal to Samidori and Asahi, the two elite hand- picked Uji tencha cultivars, which is a high bar. Tenmyo’s particular strength is external colour — it dyes well and evenly on rolling — and it readily develops the “covering aroma” (覆い香) that shaded tencha is judged on, without requiring the more labour-intensive hand- picking regime those other cultivars are usually given. Vendor descriptions of the finished matcha are consistent with this: strong umami, mild bitterness and astringency, a bright green liquor, and a smooth, faintly marine or “seaweed” note characteristic of well-shaded tea. Several growers also report it making a good gyokuro, though tencha and matcha remain its primary use.

Tenmyo is weak against anthracnose and only moderately resistant to gray blight (ring spot disease). The institute’s release announcement does not address disease resistance for either Tenmyo or Houshun, but both ratings are official elsewhere: the Plant Variety Protection Act characteristic filing gives 輪斑病抵抗性は中, and Kyoto Prefecture’s recommended-cultivar characteristics table gives 炭疽病抵抗性 弱 alongside 輪斑病抵抗性 中 — the same anthracnose rating that table gives Yabukita.

Two decades after registration, Tenmyo remains a minor cultivar in commercial terms. It solved a specific problem — quality tencha off a mechanical harvester — rather than aiming to displace the hand-picked cultivars at the top of the Uji tencha hierarchy, and single-cultivar Tenmyo matcha is still marketed by only a handful of specialist farms, mostly around Wazuka and Ujitawara.