Tortoise-shell brackets are common in Chinese official documents.
Tips
usage
Standard CJK punctuation set: 圆括号 () round, 方括号 [] square, 花括号 {} curly, 六角括号 〔〕 tortoise-shell, 尖括号 〈〉 angle. 六角括号 turns up in dictionaries (around part-of-speech tags) and in PRC official document numbering, e.g. 国发〔2024〕5号.
