Kurasawa

Kurasawa is a Shizuoka sencha cultivar selected in 1967 from open-pollinated Yabukita seedlings and never registered. It is one of a cluster of strains — retrospectively grouped as the “Shizu-7000 series” — that the Shizuoka Prefectural Tea Experiment Station pulled out of a Yabukita-seedling screening programme in the mid-to-late 1960s, and, like most of that cluster, it stayed a prefectural recommended cultivar rather than a nationally-registered one. Its two claims to notice are unrelated to registration status: a heavy, forest-like astringency that carries through to a distinctive cocoa note when it is processed as matcha, and its role three years after its own selection as the seed parent of Koshun, the aroma cultivar that did go on to be registered in 2000.

Lineage

• Yabukita — the seed-bearing parent. Kurasawa was picked out of a population of seedlings grown from Yabukita seed that had been pollinated naturally rather than by a controlled cross, so its pollen parent was never recorded and cannot now be recovered.

This is a landrace-style single-plant selection, not a controlled cross, and it sits one step further from a “clean” pedigree than Yabukita itself: Yabukita was picked from a Zairai seed-grown stand, but Kurasawa was picked from a Yabukita seed-grown stand, so it is already a second-generation open-pollinated selection with an unrecorded father on both sides of that history. It was not an isolated project — the same Shizuoka programme, working from Yabukita seed in the same few years, also produced Yamakai (trial name Shizu-7166), Suruga-wase (Shizu-7109, 1962), Fuji-midori (Shizu-7224, 1962) and Shizu-7132 (1967), Kurasawa’s own trial name being Shizu-7111. None of these five were ever submitted for national Cha Norin registration. Kurasawa’s clearest documented descendant is Koshun, a controlled cross of Kurasawa (seed parent) and Kanayamidori (pollen parent, 茶農林30号) made in 1970 and registered in 2000 — for which see the separate record of that cultivar. No cultivars bred from Kurasawa other than Koshun have been located.

History

Kurasawa was selected in 1967 at the Shizuoka Prefectural Tea Experiment Station, one line pulled from a population of naturally-pollinated Yabukita seedlings under the trial designation Shizu-7111. A retrospective slide deck on Koshun by the station’s own researchers places this selection inside a documented wave of Shizuoka cultivar work: a 1965–1974 push, driven by rising domestic demand and larger tea-processing machinery, aimed explicitly at higher-yielding, differently-timed, higher-quality cultivars, with Kurasawa named alongside Kanayamidori and Ooiwase as the releases that period produced.

“Released” is doing some work in that sentence, though, because Kurasawa itself never was, in the formal sense. Checking Kurasawa’s name against MAFF’s own 附表１茶農林登録品種一覧 — the complete table of all 52 nationally registered Cha Norin cultivars, from 茶農林1号 (Beni-homare, 1953) through 茶農林52号 (Miyamakaori, 2003) — finds no entry for it; the same absence holds for its Shizu-7000 stablemates Yamakai, Suruga-wase, Fuji-midori and Shizu-7132. A separately compiled registry (the japaneseteasommelier master list) independently classifies all five as “non-registered” strains, in a table distinct from the one listing cultivars that received formal name- and cultivar-registration. That same source explains, for one member of the group specifically, why it was passed over — Shizu-7132 tended to redden on the summer harvest, gave too dark a liquor, and was too astringent from lowland gardens, despite a prized cherry-leaf aroma. No source located gives an equivalent explanation for Kurasawa itself; none of the material consulted states a reason it was not carried forward to national registration, and this record does not invent one. What can be said is the observable pattern: Shizuoka took it up itself instead. A 2013 lecture by the head of the prefecture’s tea research centre carries a table of Shizuoka’s recommended cultivars (奨励品種) and their planted area, and Kurasawa sits in it with a recommendation running from 昭和42 (1967), the year of its own selection, to 平成13 (2001) — 9 ha of prefectural planting in 1967, a peak of 154 ha in 1976, 65 ha by 1998 and 38 ha by 2007. It was promoted, in other words, but only within the prefecture, and it was never put up for a Cha Norin number. By 1970 — three years after its selection, and already a recommended cultivar in its own right — the station was crossing it with the newly registered Kanayamidori to produce what would become Koshun, whose own path from cross to registration took thirty years and is unusually well documented by comparison. Kurasawa’s practical legacy runs through that cross more than through any release of its own.

It has nonetheless persisted in cultivation and in the market. It is currently sold as a standalone single-cultivar tea by Shinkoju (心向樹), a specialist Saitama retailer devoted entirely to named-cultivar teas, across five quality grades and four processing styles — ordinary steamed sencha, deep-steamed (fukamushi) sencha, pan-fired kamairicha, and black tea — and the same retailer sells young Kurasawa plants, meaning it is still being propagated rather than sold down from old stock. Separately, at least one producer (Houkouen) markets it as a single-estate matcha, an application distinct from the leaf teas it is more usually described in, and one retailer’s account of that matcha describes it as the only Kurasawa matcha currently on the Japanese market — a claim made by a single vendor source and not independently corroborated here.

Characteristics

Kurasawa buds in a normal, mid-season window — a “中生” cultivar in the Japanese sources, echoed by an English-language source describing it as “normal budding” — but no source gives a specific day-count relative to Yabukita, the usual convention in this collection; the prefectural material that does cover the cultivar records only the 中生 class. Multiple independent sources agree that it grows vigorously and yields heavily — heavy yield being the ground Shizuoka recommended it on — again without a specific kg/10a figure attached. No disease-resistance or cold-hardiness data has been located for it in any source consulted; the prefectural material located records its recommended-cultivar status and its planted area rather than its characteristic ratings.

The cup is where the sourcing is most consistent and most specific. Shinkoju’s own tasting copy describes a natural aroma reminiscent of forest and woodland, paired with an astringency that builds gradually and runs deep (“じわじわと深みの渋味”) rather than hitting sharply up front; an English-language source independently converges on the same pairing, describing “a distinctly refreshing aroma and intense astringency, which gives the infusion a distinctive depth.” That astringency is pronounced enough that Shinkoju’s own five-point in-house scoring rates several of its Kurasawa grades at or near the top of its astringency scale while rating umami and body only middling — a tea built around structure and aroma rather than sweetness. As matcha specifically, one retailer source is unambiguous about what sets it apart: “a unique flavor profile with noticeable notes of cocoa — rich, deep, and incredibly aromatic,” with a dense, velvety texture it recommends for a matcha latte rather than a thin usucha. That cocoa character, together with the underlying astringency, is the throughline connecting every source on this cultivar, and is the clearest reason it is still sought out on its own rather than folded into a blend, sixty years after a station researcher pulled one seedling out of a Yabukita trial plot and never bothered to put it through the registration system.