A magnificent and possibly unique ruby-ground yangcai 'trigrams' reticulated vase, Seal mark and period of Qianlong 清乾隆 御製洋彩紫紅錦地乾坤交泰轉旋瓶 《大清乾隆年製》款 of pear shape, with a revolving trumpet-shaped neck pivoting on a cylindrical inner vase, the globular body cut along a line of interlocking ruyi-heads and pierced with the eight trigrams, the bright ruby ground finely incised in sgraffiato with dense feather arabesques, reserved with stylised lotus flowers borne on curling foliage issuing additional florets and buds, the spreading foot encircled by a ruyi-band in red and blue against a vivid lemon-yellow ground with similar sgraffiato work, the waisted neck with interlinked ruyi and floral designs on a pale blue and yellow ground, flanked by two flat scroll handles enamelled in iron-red and gilt, the flaring mouth rim with leafy sprays on a pale green ground, the inner vase visible through the narrow openings, painted in underglaze-blue with lotus scrolls in early Ming style, the interior of the neck and the base enamelled in pale turquoise green, the base reserved with a six-character seal mark h. 31 cm