dyeing material
Sukumo
A Japanese indigo dye material made by fermenting dried leaves of tade-ai (Persicaria/Polygonum tinctorium). Sukumo made in Tokushima is called awa-ai.
Theme: Dissolve, then return
Claims and evidence (18)
The limitations noted for some sources are recorded in Japanese only — see the Japanese edition.
Sukumo ・propertyStates that, while the origin of indigo cultivation in Tokushima is unclear, a record of indigo shipments in the 1445 "Hyōgo Kitaseki Iri-fune Nōchō" suggests awa-ai was already being made and traded by the Muromachi period.contextual
States that although the origin of awa-ai is unclear, a record of indigo shipments in the 1445 document "Hyōgo Kitaseki Iri-fune Nōchō" suggests it was already being produced and traded by the Muromachi period.
Source: 阿波藍 (Awa-ai) （徳島県 (Tokushima Prefecture)） ・「阿波藍の歴史」の節、冒頭 ・institutional summary ・ checked against the source by AI
institutional summary ・ 
checked against the source by AISukumo ・propertyStates that awa-ai came to dominate the national market in the 1700s for three reasons it gives: growing demand for indigo as cotton cultivation expanded around Osaka, protection and encouragement of the indigo business by the Tokushima domain, and Tokushima's suitable geography and climate.contextual
States that awa-ai came to dominate the national market in the 1700s for three reasons it gives — rising demand for indigo dye as cotton cultivation spread around Osaka, technique improvements encouraged by the Tokushima domain's protection of the industry, and Tokushima's suitable geography and climate — and that this prosperity continued into the 1800s.
Source: 阿波藍 (Awa-ai) （徳島県 (Tokushima Prefecture)） ・「阿波藍の歴史」の節、中盤 ・institutional summary ・ checked against the source by AI
Sukumo ・why it fell out of useStates that after Tokushima's cultivated area for awa-ai peaked at about 15,000 ha in 1903, production fell sharply as imports of precipitated indigo from India and synthetic indigo from Europe increased.contextual
States that awa-ai's prosperity continued into the 1800s, with cultivated area peaking at about 15,000 ha in 1903, after which production plummeted as imports of precipitated indigo from India and synthetic indigo from Europe increased.
Source: 阿波藍 (Awa-ai) （徳島県 (Tokushima Prefecture)） ・「阿波藍の歴史」の節、末尾 ・institutional summary ・ checked against the source by AI
Sukumo ・why it fell out of useStates that, attributing it to the spread of cheap dyes following the invention of chemical dyes, cultivated area fell sharply from 15,000 ha in 1903 (Meiji 36) to 7,542 ha in 1907 (Meiji 40), 502 ha in 1926 (early Showa), and just 4 ha by 1965 (Showa 40).contextual
Scope: Concerns figures for the trend in cultivated area of indigo (awa-ai) in Tokushima.
States that indigo production expanded until the late Meiji era, reaching a peak scale of 15,000 ha in Meiji 36 (1903), but that the spread of cheap dyes following the invention of chemical dyes caused a sharp decline to 7,542 ha by Meiji 40 (1907), 502 ha in early Showa (1926), and just 4 ha by Showa 40 (1965).
Source: 徳島県における藍の歴史 （四国大学 藍の家 研究室） ・本文後半「明治３６年には最高の15,000ヘクタール...」 ・institutional summary ・ checked against the source by AI
Sukumo ・mechanismAccording to Aizumi Town, in the ai-konashi stage, finely chopped indigo leaves are dried in the yard from early the next morning, separated into leaf and vein with a flail, then rubbed in with an 'ai-suri' tool; in the evening, well-dried material is winnowed with a large flat basket to fully separate leaf from vein, and each is packed into straw bales and stored in the neya (fermentation bed).contextual
Describes drying chopped leaves, flailing to separate leaf and vein, rubbing with ai-suri, then winnowing in the evening to fully separate leaf from vein before bale storage.
Source: すくもの加工 （藍住町） ・「すくもの加工」ページ「1.あいこなし」 ・institutional summary ・ checked against the source by AI
Sukumo ・mechanismAizumi Town states that for nesekomi (bedding-in), once September comes the stored indigo is taken from the bed, piled up while being watered, and within 4-5 days ferments to a high temperature of 65-70°C, filling the bed with an ammonia smell so strong one can barely keep one's eyes open.contextual
States that in September the material is piled and watered, fermenting within 4-5 days to 65-70°C with an ammonia smell strong enough to make it hard to keep eyes open.
Source: すくもの加工 （藍住町） ・「すくもの加工」ページ「2.寝せ込み」 ・institutional summary ・ checked against the source by AI
Sukumo ・mechanismAccording to Aizumi Town, the piled leaves (one 'toko' or bed) are turned about 20 times in the 'kirikaeshi' process so that fermentation proceeds evenly, and this heavy labour is said to continue for roughly 100 days.contextual
States one pile (toko) is turned about 20 times in 'kirikaeshi' so fermentation is even, a heavy task lasting about 100 days.
Source: すくもの加工 （藍住町） ・「すくもの加工」ページ「3.きりかえし」 ・institutional summary ・ checked against the source by AI
Sukumo ・mechanismAizumi Town states that as finishing approaches, the leaves are covered with straw matting ('futon-kake') and left to return to ambient temperature, so that sukumo is completed in early December.contextual
States covering with matting and waiting for ambient temperature results in sukumo being finished in early December.
Source: すくもの加工 （藍住町） ・「すくもの加工」ページ「4.ふとんかけ」「5.すくも」 ・institutional summary ・ checked against the source by AI
Sukumo ・producesAccording to Aizumi Town, finished sukumo is stored packed into 60 kg bales; today it is dissolved to make dye liquor, but formerly it was shipped as ai-dama (indigo balls), and in the Chikuzen trade it is said to have been shipped as plain sukumo.contextual
Scope: The bale weight as stated by Aizumi Town
States sukumo is stored in 60 kg bales; today dissolved into dye liquor, formerly shipped as ai-dama, with the Chikuzen trade shipping it as plain sukumo.
Source: すくもの加工 （藍住町） ・「すくもの加工」ページ「6.俵づめ」 ・institutional summary ・ checked against the source by AI
Sukumo ・mechanismAccording to the Ai-no-ie laboratory at Shikoku University, the fermentation bed (doma) is built, from the surface down, of a clay layer (about 30), then rice husks (20), then sand (about 5), then gravel beneath that, said to hold down rising moisture and keep fermentation heat from escaping into the ground.contextual
Describes the layers from the surface as clay (about 30), rice husks (20), sand (about 5), then gravel, to suppress rising moisture and stop fermentation heat escaping downward.
Source: 「すくも」づくり （四国大学 藍の家 研究室） ・「すくも」づくり、「1）寝床について」「土間の構造」 ・practitioner's record ・ checked against the source by AI
practitioner's record ・ Sukumo ・mechanismThe Ai-no-ie laboratory at Shikoku University targets roughly 250 kg of finished sukumo, with the core temperature of the piled leaves reaching about 70°C. Kirikaeshi is done at least once a week, and repeating it 12 to 15 times while supplying air and moisture is said to complete the sukumo.contextual
Scope: As practised at the Ai-no-ie laboratory (laboratory-scale production)
States the target yield is about 250 kg sukumo, the core fermentation temperature is about 70°C, turning is done at least weekly, and repeating the air/moisture-replenishing turn 12-15 times completes the sukumo.
Source: 「すくも」づくり （四国大学 藍の家 研究室） ・「すくも」づくり、「２）すくも作り」1回目〜3回目以降の切り返し ・practitioner's record ・ checked against the source by AI
Sukumo ・differenceKawahito Miyoko divides indigo dye into natural and synthetic indigo, with natural indigo further divided by processing method into 'sukumo' and 'chindenai' (precipitated indigo): sukumo is made by drying then fermenting indigo leaves, whereas chindenai is made by soaking fresh leaves in water to extract the pigment.contextual
Explains indigo dye splits into natural and synthetic, natural indigo splits by processing into sukumo and chindenai, with sukumo made by drying then fermenting leaves and chindenai by soaking fresh leaves in water to extract pigment.
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P98、「２．「すくも」と阿波藍」 ・ethnographic record ・ checked against the source by AI
ethnographic record ・ Sukumo ・propertyAccording to Kawahito Miyoko, the number of farming households growing indigo changed over time: 134 in 1967, 86 in 1985, 92 in 2000, and 36 in 2013.contextual
Scope: Trend in the number of indigo-farming households in Tokushima (as tabulated by Kawahito, 2015)
States indigo-farming households numbered 134 (1967), 86 (1985), 92 (2000) and 36 (2013).
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P99〜100、「4.2 一次産業（農業）の仕事」末尾 ・ethnographic record ・ checked against the source by AI
Sukumo ・mechanismAccording to Kawahito Miyoko, in the ai-konashi stage, the cut and sorted indigo leaves are spread over a wide yard and sun-dried, a process said to take two days; the fully dried leaves (haai) become the raw material for Awa-ai.contextual
States the sorted leaves are spread in the yard and sun-dried over two days, with the fully dried leaf becoming Awa-ai's raw material.
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P99〜100、「4.3 二次産業（製造業）の仕事」 ・ethnographic record ・ checked against the source by AI
Sukumo ・mechanismAccording to Kawahito Miyoko, in nesekomi, the first stage of Awa-ai production, 3,000-3,750 kg of dried leaf per bed is mixed with an equal weight of water and piled to a height of about 1 metre.contextual
States the first production stage, nesekomi, mixes 3,000-3,750 kg of leaf per bed with an equal weight of water, piled to about 1 m high.
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P100、「4.3 二次産業（製造業）の仕事」寝せ込みの段落 ・ethnographic record ・ checked against the source by AI
Sukumo ・mechanismAccording to Kawahito Miyoko, after nesekomi, the leaves are watered and mixed every five days in the 'kirikaeshi' turning process, with second-cutting leaf added at the fourth turn.contextual
States that after nesekomi, watering and mixing ('kirikaeshi') is done every five days, with second-cutting leaf added at the fourth turn.
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P100、「4.3 二次産業（製造業）の仕事」切り返しの段落 ・ethnographic record ・ checked against the source by AI
Sukumo ・mechanismAccording to Kawahito Miyoko, after 12-13 turns, 'naka-doshi' (sieving) is performed in late October; after the 17th-18th turn in November, 'age-doshi' is performed; and Awa-ai is finished after a total of 22-23 turns. Timing varies somewhat by ai-shi, but finishing is said to take 90-100 days between September and January.contextual
States naka-doshi (sieving) follows 12-13 turns in late October, age-doshi follows the 17th-18th turn in November, totalling 22-23 turns to finish, taking 90-100 days between September and January depending on the ai-shi.
Source: 阿波藍の製造（藍師・栽培・染料作り）とその染料液の作成 （川人美洋子（一般社団法人繊維学会正会員）, 2015） ・PDF 誌面P100、「4.3 二次産業（製造業）の仕事」中通し〜上げ通しの段落 ・ethnographic record ・ checked against the source by AI
Sukumo Ash-Lye Vat Kit includes Sukumo (as a class)contextual
Scope: Sukumo Ash-Lye Vat Kit
Lists the set's contents as 240 g sukumo, 300 g wood ash, 100 g shell lime, 100 g bran, and an instruction booklet.
Source: 蒅藍建てキット（商品ページ） （株式会社田中直染料店） ・「セット内容」の一覧 ・manufacturer statement ・ checked against the source by AI
manufacturer statement ・ Open questions (2)
How large a factor, relative to synthetic-indigo imports, was imported Indian natural "precipitated indigo" in awa-ai's decline?
Tokushima Prefecture's official page names both Indian "precipitated indigo" (a natural indigo extract) and European synthetic indigo as factors in awa-ai's decline, without breaking down their relative weight; Shikoku University's page attributes the decline only to "the invention of chemical dyes", without mentioning Indian natural indigo at all. The relative scale and timing of natural Indian vs. synthetic European indigo imports pressuring awa-ai could not be confirmed in our search.
Why do the number of 'kirikaeshi' turns and the weight per bale of sukumo differ so much between sources?
Aizumi Town's 'Ai no Yakata' museum gives about 20 turns over about 100 days; the Ai-no-ie laboratory at Shikoku University gives 12-15 turns; and Kawahito Miyoko (2015) gives 22-23 turns over 90-100 days. Bale weight also differs: 60 kg (Aizumi Town) versus about 56.25 kg, i.e. 15 kan (Kawahito, 2015). Whether this reflects differences between individual ai-shi, years, or scale of production, or simply different ways of counting a 'turn' or a 'bale', could not be confirmed.