20th century Of flattened ovoid shape Peking milk glass snuff bottle with red overlay representing the 'Ying & Yang' and a bat motif, both shoulders decorated with mask motifs Fine work with uncommon Ying & Yang design With a green calcite stopper 6.5cm high 39g Provenance: Private collection, Singapore, acquired in 1973; and thence by descent to the present owner Note: The concept of yin-yang has a long history. There are many written records about yin and yang, some dating back to the Yin dynasty (about 1400–1100 BCE) and the Western Zhou dynasty (1100–771 BCE). In Chinese philosophy is a concept of dualism describing how seemingly opposite or contrary forces may actually be complementary, interconnected, and interdependent in the natural world, and how they may give rise to each other as they interrelate to one another