 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.The 1298 book "Zao Huozi Yinshufa" (《造活字印书法》/《造活字印書法》) by the Yuan dynasty (1271–1368) official Wang Zhen mentions tin movable type, used probably since the Southern Song dynasty (1127–1279), but this was largely experimental.It was unsatisfactory due to its incompatibility with the inking process.