In the "Shuowen Jiezi" (Shuowen Jiezi), the character "正" (zhèng) was historically written as "㱏" (zhèng), composed of "二" (èr). "二" is the ancient character for "上" (shàng). For detailed commentary, see the stroke count under Radical: One (yī). Furthermore, in the "Jiyun" (Jiyun), the character "定" (dìng) was historically written as "㱏" (zhèng). For detailed commentary, see the fifth stroke under Radical: Roof (mián).