Apart from the current Czech hallmarks (see picture above), all hallmarks that were valid in the history of Czechoslovakia and did not express a lower purity than the lowest purity for individual precious metals specified in the Hallmarking Act (§3, paragraph 2) are valid. Thus, the marks of the Austro-Hungarian, Czechoslovak, Protectorate and Slovak State marks. An example is the hallmark called the Čejka, used until 1993 for the 585/1000 purity. However, the hallmarks that were introduced during World War II on Czechoslovak territory occupied by foreign states (Austrian, Polish and Hungarian marks) are not valid. Other valid historical marks are published in the brochure ing. Bouša "List of hallmarks valid on the territory of the Czech Republic", first published in 2008, reissued in 2018. It is available at each PU office and in electronic form.