Lacquer timber surface gives heavy blackening: The likelihood is knag going up Qi Qian was not sealed, classics sun is basked in, knag be heated, colophony from knag inside oozy and cause.

漆木出沉暗斑：可能是木节在上漆未封住，经太阳一晒，木节受热，木节内渗出而引起的。