Asanoka

Asanoka is a sencha cultivar bred at the Kagoshima Prefectural Tea Experiment Station and registered in 1996, crossed from Yabukita and the Chinese cultivar Pingshui No. 1, carried in the breeding record as Cp1. It is grown as a regional specialty rather than at national scale, valued chiefly for a distinctive varietal aroma, a finely rolled leaf with good colour, and an unusually high amino acid content that has made it a subject of research into low-nitrogen, organically-managed cultivation. Trade coverage treats it as one of the more interesting cultivars to come out of Kagoshima in the 1990s without ever suggesting it displaced Yabukita there; a 2019 reference work on tea cultivars still describes it as “locally notable” rather than mainstream.

Lineage

• Yabukita female — the industry benchmark cultivar, contributing a reliable, balanced base onto which Asanoka’s aroma is layered.
• Cp1 male — the Chinese cultivar 平水1号 (Pingshui No. 1), named as 中国種「平水1号」in MAFF’s registration record. See “The identity of Cp1” below.

This is a controlled cross, not a landrace selection: Asanoka was deliberately bred and then selected from the resulting seedlings, though no source gives a crossing or selection year — the earliest dated step on record is the variety-registration application of 31 January 1994. No cultivars are documented as descendants of Asanoka, and it does not appear to be a parent in any other registered cultivar’s pedigree found in this research.

History

Kagoshima Prefecture applied to register Asanoka on 31 January 1994 and the registration was granted on 19 March 1996 as registration no. 5013; breeder’s rights lapsed on 20 March 2014. Notably, it does not carry a 茶農林 (Cha Norin) number: the national MAFF registry of Cha Norin-numbered cultivars runs from 茶農林41号 (Fushun, 1991) to 茶農林42号 (Minamisayaka, 1991) to 茶農林43号 (Hokumei, 1992) to 茶農林44号 (Benifuuki, 1993) and then jumps straight to 茶農林45号 (Ryofu, 1997) — no number was issued for 1994–1996. Asanoka was registered by the prefecture under the Seed and Seedling Law (種苗法) — the Plant Variety Protection Act framework — rather than through the national Cha Norin system, which several sources bear out by listing it separately as a Seed-and-Seedling-Law-registered rather than MAFF-registered cultivar.

Trade press picked it up twice in the years after registration: a 1998 feature in the industry magazine 「茶」grouped it with Hokumei and Mie Midorimoe No. 1 as a notable cultivar bred by a major tea prefecture, and a 2001 profile in the same magazine singled it out by name — “いま注目の品種を見る(23) あさのか” (“Cultivars worth watching now, no. 23: Asanoka”) — describing it as finely rolled, of excellent colour, and high-yielding. More recently, a 2023 paper in the JATAFFジャーナル developed a pruning technique specifically to reduce net blister blight (mochi disease) incidence in Asanoka grown under organic management, which places it among the cultivars Kagoshima growers are using for chemical-free production. None of this amounts to wide adoption: a 2019 reference book from the Shizuoka Tea Industry Council, 茶の品種 新版, still files Asanoka under “ローカルながら注目したい品種” — cultivars that are local rather than national in reach but worth paying attention to regardless.

The identity of Cp1

MAFF’s registration record settles what Cp1 is: it describes Asanoka as bred by crossing 「やぶきた」with the Chinese variety 「平水１号」— Pingshui No. 1, named for the Pingshui green-tea district of Zhejiang. The code Cp1 is a contraction of that name, its “C” standing for the Chinese-type (中国種) germplasm the programme held; the same national registry table that documents the Cha Norin series records 茶農林22号 Benifuji (1960, bred at Kanaya) as a cross of Benihomare × C19, apparently a second such line, though no source consulted spells that convention out. Cp1 also turns up as test material outside Asanoka’s own paperwork: a 1988 chloroplast-DNA study published in 茶業研究報告 examined leaf material from six named tea lines — A6, Kan6, Ck17, Cp1, Yabukita and Yamatomidori — alongside the wild relative Camellia taliensis, and discusses its result in terms of differences among “アッサム雑種、中国種、日本種” (Assam hybrids, Chinese types and Japanese types) found within the C. sinensis material tested. What no source found here gives is Pingshui No. 1’s own introduction history into Japan — when it was brought in, by whom, and into which collection.

Characteristics

Asanoka buds slightly early (やや早生): MAFF’s registration record classes both budding and plucking at the breeding station one step ahead of mid-season, but no source gives a specific day-count relative to Yabukita, so its position within the wider early/late spread this collection otherwise measures in days cannot be stated precisely. It is also notably cold-hardy — the registration record rates resistance to red and blue withering 強 and to split-type freeze injury 極強. Growth is vigorous, particularly in the second flush — summer growth is described as strong — and yield is reported as high on young bushes and slightly high (やや多) on mature ones, with trade coverage flattening this to “多収” rather than a published kg/10a figure.

In the cup and in the dry leaf, Asanoka is known for three things: a distinctive varietal aroma unlike Yabukita’s grassy character, a balanced flavour with a mellow, mild finish, and — worked into leaf — a fine, tightly rolled shape with good colour and lustre, praised specifically in a 1998–2001 trade assessment. Underlying the mellow taste is an unusually high amino acid content: research into tea cultivars suited to reduced-nitrogen fertilisation found that Asanoka retains notably higher amino acid levels in its winter wood tissue than the other cultivars tested, and shows correspondingly high nitrogen-utilisation ability above ground — the basis for its being positioned as a candidate for environmentally lower-input, organic cultivation rather than for maximum yield under heavy fertilisation.

That organic suitability comes with at least one specific disease caveat: net blister blight (もち病) was significant enough in organically grown Asanoka that researchers developed and published a pruning-based technique in 2023 specifically to reduce its incidence, since organic management rules out the fungicide route available to conventional growers. The registration record gives no rating for net blister blight, but it does rate anthracnose resistance やや弱 (somewhat weak) against gray blight at やや強, so the honest reading is that Asanoka is grown organically in Kagoshima despite, not because of, an easy disease profile. It is sold primarily as sencha and fukamushi (deep-steamed) sencha, but at least one specialist single-cultivar retailer also processes it as kamairicha (pan-fired tea) and as black tea, suggesting real versatility in processing — though sencha remains its documented primary and registered use.