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United States (Apurva Mehta, Martin Kunz and Tamura Nobumichi) undertook
a study of Jian ware glazes using a wide range of investigative techniques -
including optical microscopy, electron microscopy, Raman spectroscopy and
synchroton x-ray techniques, which was published in 2014 as ‘Learning from
the Past: Rare ε-Fe2O3 in the ancient black-glazed Jian (tenmoku) wares’,
in Scientifc Reports 4:4941; doi:10.1038/srep04941. Previous studies had
concluded that the iron oxides which provided the streaks in the Jian ‘hare’s
fur’ glaze were hematite (a-Fe2O3), and that the crystallized iron in the shining
silver spots on the ‘oil spot’ glaze were magnetite (Fe3O4). The scientists in
the 2014 study were astonished to fnd that the crystals in the ‘oil spot’ glaze
were in fact remarkably pure ε-Fe2O3 phase (the epsilon phase), a very rare
and metastable relative of hematite. (Smaller quantities of ε-Fe2O3 were
found in the Jian ‘hare’s fur’ glaze, but these were mixed with hematite.) The
fnd in relation to ‘oil spot’ glazes is remarkable, not least because this epsilon wenjian ji (封氏聞見記 Things Seen and Heard by Mr. Feng) the author notes
phase was only identifed by scientists in 1934, while its crystalline structure
has only been known since 1995, and only understood since 2005. It is a
material that has important applications in the modern world, but it has proved
very hard to make in laboratories – the crystals produced there being very
small and contaminated by other phases. The epsilon phase crystals in the
Jian ‘oil spots’ are not only signifcantly larger than those produced by modern
methods, but are also exceptionally pure.
The high-point of production for Jian ware tea bowls appears to have been
the period between the mid-Northern Song and the mid-Southern Song
dynasty. However, the excavations undertaken at the Jian ware kiln site of
Luhuaping (蘆花坪) in 1977, revealed the remains of a Five Dynasties kiln
producing celadon wares, which was discovered directly beneath the black
wares kiln (see Zeng Fan, ‘Fujian taoci de lishi’, appendix to Zhongguo Taoci
Bianji Weiyuanhui, Fujian Taoci, Zhongguo Taoci, Shanghai, 1988, section 5)
– suggesting that the black wares were being made in the late Five Dynasties-
early Northern Song period. Such an early date is also suggested by a passage
in the Qingyi Lu (淸異錄), attributed to Tao Gu (陶穀), and written sometime
262
between AD 960 and 970, right at the beginning of the Song dynasty, where
the author notes that tea bowls from Fujian were particularly treasured by
connoisseurs, and have glazes resembling the spots of partridge feathers.
This would seem to be a direct reference to Jian wares and suggests that they
were produced as early as the 10th century.
There were a number of factors which contributed to the rise in popularity of
black-glazed wares during the Song dynasty. Not only were the potters able to
create black glazes with rich depth of colour and glossy surface, but changes
in tea culture in China necessitated tea bowls which had dark glazes. While
the drinking of tea was already customary in the south of China by the early
Tang dynasty, it only spread to the rest of China in the 8th century – possibly
as a corollary of the spread of Chan Buddhism. In the late 8th century Fengshi
that a requirement of Chan Buddhism was that aspirants had to forgo sleep
and abjure the partaking of food in the evening, but were allowed to drink tea.
Mr. Feng explains that the Chan Buddhists carried tea with them wherever
they went and that people copied them, thus spreading the tea-drinking habit.
The drink became very popular not only with the scholar-oficial class, but even
with emperors, and the Song Empeor Huizong (r. 1101-25), who was famous for
his refned tastes and was a great connoisseur of tea, wrote a twelve-chapter
treatise on tea, Daguan Cha Lun (大觀茶論 Discourses on tea in the Daguan
era, 1107-1110), published in 1107. Thus tea drinking became a much more
sophisticated activity in the Song dynasty, and acquired a considerable degree
of elegance, which was refected in the vessels made for its consumption.
During most of the Tang dynasty tea was made by adding the fnely ground
tea powder to boiling water in a cauldron, but towards the end of the dynasty
another method became popular. In this method, which became the norm in
the Song dynasty, boiling water was poured from a ewer onto powdered tea
which had already been placed in a tea bowl. Even the tea used in this method
was diferent from that previously employed. In the Song dynasty there was