The cathedral is faced with pale grey limestone, easily chiselled, but hardening on exposure.
For example, on the surface of a shibuichi box-lid we see the backs of a flock of geese chiselled in silver, and when the lid is opened, their breasts and the under-sides of their pinions appear.
A still higher achievement is to apply to the chiselled base designs executed in colored enamels, finally covering the whole with translucid paste.
The decorative design having been completely chiselled in the round, is then fixed in a field of a different metal, in which a design of exactly similar outline has been cut out.
They wen decorated with blue under the glaze, but some were pure whit with exquisitely chiselled designs incised or in relief.