1914-1919 Peking 1st print Hall of Classic $2, with inverted central printing variety (Chan 245a), MH.
Peking 1st print Hall of Classic used bi-colour printing which means the frame was printed first then the central design. However, the printers wrongly placed two complete sheets upside down. 100 such variety stamps were produced and only about 30 have survived. It is known as one of the “Four Treasures of the Republic” (民國四珍).
1914至1919年北京一版宮門2元新，帶中心倒印變異「宮門倒」（陳目245a），背貼。
北京一版宮門以雙色套印印製，一般先印邊框，後印中心圖案。然而印刷中誤將兩張全張倒置，故印製了一百枚宮門倒，當中存世者僅約三十枚，被稱為「民國四珍」之一。