The ethereal sky-blue color and extraordinarily tactile, almost silken, quality of the glaze on the present washer in many ways encapsulates the ideal celadon glaze. Generations of potters from various kilns strived to achieve such a fine texture and color, but it was rarely achieved outside the imperial Ru and Guan kilns. Even the imperial Guan wares display considerable color variations, and large numbers of pieces which fired to less-than-ideal colors were discarded in designated pits: see Hangzhou laohudong yaozhi ciqi jingxuan (Select Ceramics from Laohudong Kiln Site in Hangzhou), Beijing, 2002, p. 16 and pp. 24-25. The production of high-quality celadon wares at the Longquan kilns were influenced by the establishment of the Guan kiln after the Song court settled in Hangzhou: see Zhu Boqian (ed.), Celadons from Longquan Kilns, Taipei, 1998, p. 17. However, since the craftsmen at Longquan mainly produced commercial wares made mostly for middle and upper class patrons, they did not have the luxury of selecting only perfectly-fired examples for their clientele. Longquan wares from the Southern Song dynasty typically exhibit thick, unctuous glazes of bluish-green or green color, with the best examples being recognized by the Japanese term ‘kinuta’. It is, however, extremely rare to find a Longquan glaze of sky-blue color such as that seen on the present washer, which might be compared to the Ru and Guan glazes.
The exceptionally fine potting of this washer also distinguishes it from other Longquan wares. The thin and neat trimming of the foot is similar to Guan wares, such as the examples illustrated in Catalogue of the Special Exhibition of Sung Dynasty Kuan Ware, Taipei, 1989, nos. 89, 90, 91, and 100, and is different from other commonly seen Longquan examples of this form, such as the one found in the Jinyucun hoard in Sichuan province, illustrated in Jinyucun Hoard of Southern Song Dynasty in Suining, vol. 2, Beijing, 2012, pl. 61. Some scholars suggest that the Longquan kilns also produced high-quality wares for the court when needed: see Rose Kerr, Song Dynasty Ceramics, London, 2004, p. 89. The present washer is likely to be one of these tribute pieces to the court.
A pair of Longquan washers of this type, but with typical greenish-celadon glaze, in the MOA Museum of Art, Atami, is illustrated in Song Ceramics, Tokyo, p. 108, no. 71. Another similar Longquan washer in the Idemitsu Museum of Art, Tokyo, is illustrated in Kuboso Memorial Museum of Art, Sensei, Bansei and Celadon of Longquan Yao, Izumi, 1996, p. 16, no. 48. Compare, also, Longquan washers of this form found in the Jinyucun hoard in Sichuan province, and illustrated in Jinyucun Hoard of Southern Song Dynasty in Suining, vol. 2, Beijing, 2012, pls. 62-64.