Inaguchi

Inaguchi is a minor Shizuoka sencha cultivar that began as pure chance rather than as anyone’s breeding programme. A grower surnamed Inaguchi found a Yabukita seedling growing in his own tea field in present-day Shizuoka city — the same city, though not necessarily the same district, where Sugiyama Hikosaburo had found the original Yabukita eight decades before — and propagated it himself because of its deep green colour and apparent vigour. The Shizuoka Prefectural Tea Industry Experimental Station later confirmed the plant’s colour, shape and aroma were good enough to register, and it was registered in 1988 under the Plant Variety Protection Act. It buds only a day or two after Yabukita and yields about the same, so it reads less as a deliberate improvement on the reference cultivar than as an incidental variant of it, and it has stayed a small, local planting: it does not appear in Shizuoka Prefecture’s own guidebook of recommended cultivars, nor in any of the general reference hubs checked for this record.

Lineage

• Yabukita — the seed parent. The plant grew from an open-pollinated Yabukita seed found in a Shizuoka tea field, not from a deliberate cross.

This is an open-pollinated selection, not a controlled cross: Mr. Inaguchi found the seedling growing by chance rather than crossing chosen parents by hand, so its pollen parent was never recorded and cannot now be known. It sits one step removed from a landrace selection like Yabukita’s own — Yabukita’s seed parent is an anonymous Zairai (seed-grown, unnamed) bush, while Inaguchi’s seed parent is specifically the named cultivar Yabukita, making Inaguchi a chance “Yabukita seedling” rather than a Zairai one. Deliberately bred Yabukita-seed cultivars exist too — Sayamakaori (茶農林31号) is a controlled Yabukita-seed selection from Saitama, for instance — but Inaguchi’s own case is closer to Yabukita’s original story: an individual grower spotting one good plant among many and keeping it. No descendants of Inaguchi are documented in the sources found here.

History

Inaguchi’s origin is recorded only in outline. A grower whose surname was Inaguchi discovered the plant by accident in his own tea field in what is now Shizuoka city; because it stood out for its deep green colour and appeared to grow well, he began propagating it by cuttings rather than treating it as one more seedling among many. The Shizuoka Prefectural Tea Industry Experimental Station evaluated the resulting plant in 1986 and judged its colour, shape and aroma good enough to be worth registering; it was registered two years later, in 1988, under the seed and seedling law — the Plant Variety Protection Act, in its modern rendering — rather than through the nationally coordinated Cha Norin (茶農林) trial programme.

That distinction is worth stating plainly, because the absence is itself informative. A full appendix table of all 52 Cha Norin registrations, spanning 1953 to 2003, contains no entry for Inaguchi, and NARO’s own tea cultivar handbook — which covers only cultivars bred with national funding, including those entrusted to Saitama’s and Miyazaki’s prefectural stations — does not include it either, for the same reason: Inaguchi was never part of that programme. It was a single grower’s find, registered in his own name rather than an institution’s. Shizuoka Prefecture’s own guidebook of cultivars it actively promotes (注目されている茶品種ガイドブック) also has no entry for it, which is consistent with a cultivar that was registered but never pushed as a recommended planting. What the record does carry is the Plant Variety Protection Act filing itself, held in MAFF’s 登録品種データベース: application No. 2120, filed 21 January 1987, registered as No. 1676 on 18 August 1988, with 稲口勝利 (Inaguchi Katsutoshi) of Niima, Shizuoka city named as both the registrant and the sole person who bred the variety — no institution, no team. Beyond that filing there is no release paper: J-STAGE, CiNii and the National Diet Library’s catalogue all return nothing under either いなぐち or 稲口 in connection with tea, which is itself consistent with a cultivar that entered the record through an individual’s registration rather than through an institutional breeding trial with its own published chronology. The breeder’s rights lapsed on 19 August 1994, six years into an eighteen-year term.

Characteristics

Inaguchi buds only one to two days after Yabukita, placing it squarely in the mid-season band alongside the cultivar it grew from. Mature leaves are slightly large with a long oval shape, deep green and notably glossy; young leaves share the same shape and colour but run to medium size, and the leaf itself is slightly thick and soft. Yield at harvest is reported as similar to Yabukita’s.

Disease resistance is fairly strong against anthracnose and medium against ring spot (grey blight) — both ratings taken from the registration filing, which notes that both are nonetheless an improvement on Yabukita’s. It is reported very weak against bacterial shoot blight, which is the trait most worth flagging for anyone considering it: a planting without careful spray management would be exposed on that front. That last rating comes from a secondary source only; the registration filing carries no bacterial shoot blight figure. Cold tolerance, by contrast, the filing does rate, and rates strong: resistance to red-scorch winter injury (赤枯れ) is 強.

In the cup, the brewed liquor runs yellow-green, with a sweet taste carrying umami and a subtle astringency; the aroma is sweet, fresh and a little floral. Beyond that description, though, the honest limit of this record is how little is corroborated: outside the registration filing’s own characteristic table only one source found gives a full characterisation of Inaguchi’s flavour and agronomy, and none of the broader English or Japanese cultivar hubs checked for this record carry an entry for it at all. It is a genuinely minor, thinly documented cultivar rather than one this record can describe with the same confidence as Yabukita or its better-known relatives.