Brush Pot with 'Lichen Spots' Monochrome Glaze, Kangxi Period (1662–1722), Jingdezhen: A Bayson-Method Diagnostic and Technological Study

This study presents a detailed examination of a porcelain brush pot (bitong) from the Kangxi period (1662–1722), produced at the Jingdezhen kilns, decorated with a complex monochrome glaze exhibiting the so-called “lichen spots” effect. The analysis applies the Bayson diagnostic method, integrating morphological, stylistic, technological, and comparative museum evidence, alongside proposed non-destructive analytical testing (pXRF and Raman spectroscopy). The brush pot combines a copper-based peach-bloom glaze with intentional green mottling, controlled glaze runs over triple ribbed relief, and an interior/foot-well guan-type crackle glaze on a dense iron-rich porcelain body. These features are consistent with documented high-quality Kangxi wares for the scholar’s studio.

Keywords: Kangxi period, brush pot, bitong, monochrome glaze, lichen spots, peach-bloom, guan-type crackle, Bayson method, Jingdezhen kilns.

1. Introduction

The Kangxi reign of the Qing dynasty (1662–1722) is celebrated for technical and artistic innovation in porcelain production, particularly in the refinement of monochrome glazes. Among these, the “peach-bloom” (江兆紅) family of copper-based glazes stands out for its elusive colour variations — from soft rose to moss green — achieved through delicate manipulation of firing atmosphere. The present study focuses on a brush pot (bitong) exhibiting a rare “lichen spots” surface pattern, in which green speckles and dark olive glaze runs interrupt the pinkish ground. This aesthetic, although seemingly accidental, reflects deliberate kiln control to induce transmutation and fluidity effects.

In addition to aesthetic evaluation, this article employs the Bayson method — a structured diagnostic approach — to document and interpret the morphological, technological, and stylistic features of the object.

2. Object Data

• Object: Brush pot (bitong)

• Material: High-fired porcelain; complex copper-based monochrome glaze with green “lichen” spots; interior and foot-well guan-type crackle glaze.

• Kiln: Jingdezhen

• Date: Kangxi period (1662–1722)

• Provenance: Private scholarly collection

• Dimensions: H × D ≈ 1.3:1 ratio (exact measurements to be recorded)

• Weight: To be recorded

3. Morphology and Form

The vessel is cylindrical with three evenly spaced horizontal raised ribs. The lip is slightly thickened and rounded, typical of high-quality Kangxi bitong. Proportions correspond to late 17th–early 18th-century scholar’s studio vessels.

4. Glaze Description

• Exterior: Pink to rose copper-derived ground with mottled green (Cu²⁺) speckles and dark olive glaze runs along the ribs. The runs exhibit controlled fluidity over relief, indicating deliberate glaze formulation for viscosity and surface mobility during firing.

• Rim: Narrow rubescent band transitioning into the body glaze, consistent with the peach-bloom glaze family.

• Interior & Foot-Well: Pale grey-blue transparent glaze with dense network crackle, imitating guan-type wares of the Song dynasty.

5. Body and Foot

The porcelain body is dense, with an iron-rich tonality visible on the unglazed foot ring. The recessed central “coin” well is glazed with the same pale grey crackle glaze as the interior.

6. Technological Interpretation

The glaze application likely involved multiple stages:

1. Application of interior/foot-well guan-type crackle glaze.

2. Exterior copper-red (peach-bloom) base glaze.

3. Over-spraying or brushing to produce green “lichen” speckles.

4. High-temperature reduction firing, followed by local oxidation during cooling, producing coexisting red and green tones and controlled runs over relief.

7. Bayson Diagnostic Matrix

8. Proposed Non-Destructive Testing

• pXRF Mapping: Analyse rim, runs, green spots, pink ground, foot; expected Cu enrichment in red/green zones, Fe at foot.

• Raman Microscopy: Characterise glass network (Qⁿ distribution); detect metallic Cu⁰ and Cu₂O phases; map green speckles for Cu²⁺ phases.

• Optical Microscopy: Examine crackle infiltration, bubble population, flow front morphology.

• UV/Vis Reflectance: Capture red/green coexistence curves to confirm transmutation behaviour.

9. Comparative Museum Examples

• The Met, Brush Washer, Kangxi mark and period: Peach-bloom glaze with greenish spots.

• Walters Art Museum, Peach Bloom Brush Washer: Apple-green flecking on mottled red ground.

• The Met, Water Pot: Described with “tender flushes of moss green” in peach-bloom glazes.

• Marchant Asian Art: Brush pot with recessed glazed centre (“coin” foot well) comparable to present example.

10. Condition

The object appears unrestored, with naturally toned crackle, minor kiln flaws (pinholes, bubble marks) consistent with period manufacture.

11. Conclusion

The brush pot can be attributed to the Jingdezhen kilns during the Kangxi period (1662–1722). Its copper-based transmutation glaze with “lichen spots” and controlled runs, combined with guan-type crackle glaze inside and in the recessed foot-well, aligns with high-quality scholar’s studio wares of the period. Both morphological and technological features, supported by comparative museum evidence, substantiate this attribution.

12. References

1. The Metropolitan Museum of Art. Brush Washer, Kangxi mark and period. Gallery 219.

2. Walters Art Museum. Peach Bloom Brush Washer (1662–1722).

3. The Metropolitan Museum of Art. Water Pot, description notes “tender flushes of moss green” in peach-bloom glazes.

4. Hou, J., et al. (2022). Birth of copper-red glaze: firing atmosphere and optical properties.

5. Colomban, P., et al. (2024). Non-Invasive Raman Classification with pXRF of Chinese Monochrome Glazes.

6. Marchant Asian Art. Underglaze copper-red & celadon brush pot with recessed glazed centre.