The typical example of this kind of bronze movable type embedded copper-block printing is a printed "check" of the Jin Dynasty with two square holes for embedding two bronze movable-type characters, each selected from 1,000 different characters, such that each printed paper note has a different combination of markers. A copper-block printed note dated between 1215 and 1216 in the collection of Luo Zhenyu's "Pictorial Paper Money of the Four Dynasties", 1914, shows two special characters – one called "Ziliao", the other called "Zihao" – for the purpose of preventing counterfeiting; over the "Ziliao" there is a small character (輶) printed with movable copper type, while over the "Zihao" there is an empty square hole – apparently the associated copper metal type was lost. Another sample of Song dynasty money of the same period in the collection of the Shanghai Museum has two empty square holes above "Ziliao" as well as "Zihou", due to the loss of the two copper movable types. Song dynasty bronze block embedded with bronze metal movable type printed paper money was issued on a large scale and remained in circulation for a long time.